Browsing by Author "Shashikala, H.D."

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?(3) measurements and optical limiting in dibenzylideneacetone and its derivatives
(2006) Kiran, A.J.; Chandrasekharan, K.; Nooji, S.R.; Shashikala, H.D.; Umesh, G.; Kalluraya, B.
We investigated the third order nonlinear optical properties of dibenzylidene acetone (1,5-diphenyl-1, 4-pentadeine-3-one) and its derivatives. The nonlinear measurements were performed by using single beam Z-scan technique with Q-switched Nd:YAG nanosecond laser pulses at 532 nm. Open aperture data for dibenzylidene and its derivatives demonstrate the presence of two-photon absorption at this wavelength. The dependence of ?(3) on donor/acceptor type substituents to the basic compound clearly shows the electronic origin of nonlinearity and hence demonstrates that the mechanism by which the third order nonlinear response enhanced is not by the thermal effects, but instead due to the strong nonlinear absorption and nonlinear refraction of the compounds. The derivatives of the basic compound show very good optical limiting behavior. © 2005 Elsevier B.V. All rights reserved.
A comprehensive study uncovering physical, structural, and optical properties of Cu2O and TiO2-reinforced borosilicate glasses as optical filters
(Elsevier B.V., 2024) Raghuvanshi, V.; Rashmi, I.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.
In this study, the integration of transition metal oxides (TMOs), specifically Cu2O and TiO2, into a borosilicate glass matrix (30SiO2–35B2O3–35Na2O–5CaF2-X (TMO)) was investigated for enhanced glass functionality. Glass samples with varying TMO concentrations (X = 0, 1, 2, 3, 4 mol%) were prepared using the melt-quenching technique. X-ray diffraction confirmed the amorphous nature of the synthesized samples, while FTIR analysis showed structural changes, transitioning from trigonal BO3 to BO4 tetrahedra, alongside the formation of non-bridging oxygen species due to TMO integration. UV–Vis spectroscopy demonstrated a red shift in optical absorption profiles, correlating with a reduction in the indirect band gap as TMO content increased. Photoluminescence studies showed distinct behaviors, with Cu2O suppressing emission peaks and TiO2 exhibiting intriguing blue and green emissions, diminishing at higher concentrations. It was attributed that Cu2O had a larger impact on altering the glass network than TiO2. These findings contribute to understanding the properties of Cu2O and TiO2-containing borosilicate glasses, suggesting tailored optical properties for potential applications as bandpass filter and UV blocker. © 2024 Elsevier B.V.
A study on the influence of geometric coordination of cobalt ions on the structural, physical and optical properties of borosilicate glass
(Elsevier Ltd, 2025) Raghuvanshi, V.; Rashmi, R.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.
This work explores the synthesis and characterization of cobalt oxide-added borosilicate glass using the melt-quenching technique. The glass system was investigated using various methods, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), density measurements, UV–vis spectroscopy, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy. XRD validated the glass's amorphous nature, while FTIR results indicated significant bonding alterations, showing a transition from BO3 to BO4 units and from B3-O-Si to B4-O-Si linkages. The increased glass density further supported the formation of BO4 units. XPS analysis verified the presence of Co2+ and Co3+ ions within the glass matrix. Optical absorption studies revealed distinct electronic transitions for Co2+ ions in both tetrahedral and octahedral coordination, and for Co3+ ions in octahedral coordination, which was corroborated by EPR spectroscopy. The paramagnetic nature of Co2+ ions was analyzed, and the g-value was determined using X-band frequency. The study also noted the narrowing of the indirect band gap with the rise in the content of Co3O4, and the examination of the metallization criterion suggested a potential metallic nature for the synthesized glasses. Notably, the 0.05 mol% Co3O4-added sample exhibited a 48 % transmission rate and the highest emission, highlighting its potential as an optical bandpass filter. These findings underscore the versatility and tunability of cobalt oxide-added borosilicate glass for various optical technologies. © 2024 Elsevier Ltd and Techna Group S.r.l.
Anomalous Photoluminescence Behavior and Judd–Ofelt Analysis of Erbium-Barium Borate Glass Embedded with Copper Oxide Nanoclusters
(Springer, 2024) Ingle, A.; Shashikala, H.D.
Glasses doped with rare earth elements have been extensively researched for the purpose of creating novel and effective photonic devices. The impact of the LSPR of metallic nanoparticles on rare earth–doped glass for manipulating luminescent properties is a new matter of study. As a result, the localized surface plasmon resonance (LSPR) of metallic nanoparticles (NPs) in amorphous materials may create new opportunities in the disciplines of optics and photonics. Therefore, erbium-barium borate glasses with a 60B2O3-38.5BaO-1.5Er2O3-xCu2O-xSnO (x = 0, 1, 2, 3, 4, 5 mol%) composition were synthesized by the melt quenching technique. The synthesized glasses were then preliminarily subjected to HR-TEM, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopic analysis for structural investigation. A consistent linear trend was observed for Cu2O concentrations from 1 to 4 mol%, but a remarkable nonlinear anomaly emerged beyond the threshold concentration of 5 mol% Cu2O. This inflection point played a pivotal role, leading to the formation of Cu0, as confirmed by LSPR in UV–visible spectroscopy, significantly impacting the glass properties. Spectroscopic attributes, including branching ratio and stimulated emission cross section, underwent notable changes, particularly at 5 mol%, showcasing enhanced branching from 13.17 to 19.20% and quantum efficiency from 28.91 to 36%, positioning BEC5 as a promising candidate. The incorporation of copper nanoparticles up to the optimized threshold level allowed for the customization of overall glass attributes. Also, a discernible shift observed in chromaticity coordinates from green to yellow region draws attention to tunable display application. The current study intends to improve the understanding of the interactions between the compositional, structural, and optical properties of copper oxideembedded erbium-barium borate glasses for photonic and lasing applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Application of Taguchi method for optimization of process parameters of melt-quenching technique for microhardness
(American Scientific Publishers, 2016) Narayanan, M.K.; Shashikala, H.D.
Ternary barium phosphate glass of maximum hardness among the composition (50-X)BaO-XCaF2-50P2O5(X = 0, 10, 20 mol%) has been obtained by optimizing parameters of melt-quenching process such as CaF2 content, melting temperature and melting time. Optimization is carried out using Taguchi’s design of experiments. Optimum condition of process parameters needed to achieve highest hardness was obtained from main effects plot and response table. Reliability and repeatability of the method were confirmed by comparing experimental value of hardness obtained by conducting the confirmatory experiment at optimum level of process parameters with predicted value. © 2016 American Scientific Publishers. All rights reserved.
Chalcones: Possible new materials for third-order nonlinear optics
(Nova Science Publishers, Inc., 2011) Kiran, A.J.; Chandrasekharan, K.; Kalluraya, B.; Shashikala, H.D.
'Search for potential materials' for third-order nonlinear optics has been of continuing interest in recent years. In this context, organic molecules are increasingly being recognized as the materials of the future because their molecular nature combined with the versatility of synthetic chemistry can be used to alter and optimize molecular structure to maximize third order nonlinear response. Chalcones have received considerable interest as materials for second-order nonlinear optical applications due to their ability to crystallize in noncentrosymmetric structure and their blue light transmittance. Being charge transfer compounds, chalcones can also possess large thirdorder nonlinearities due to their π-conjugated structure. In this article, we discuss the structure-nonlinear response relationship among a few chalcones and the possibility of using them for third-order applications. A meager or no work, to our knowledge, has been done so far on these molecules in this regard. Z-scan and degenerate four-wave mixing techniques were employed to investigate third-order optical nonlinearities of chalcone derivatives. Some of these molecules possess large χ (3) of magnitude as high as 10-12 esu and exhibit strong optical limiting properties. Possible mechanisms that are responsible for optical limiting property of these molecules have been discussed. . © 2011 by Nova Science Publishers, Inc. All rights reserved.
Corrosion Behaviour and Characterization of Thermal Sprayed Coating of Nickel Chromium Cermet on Low Carbon Steel
(2018) Amudha, A.; Shashikala, H.D.; Nagaraja, H.S.
Corrosion is the major problem faced by Navy, especially when pumps, ship impellers and other components have to work in harsh environments like sea water. Therefore, high corrosion resistant metal ceramic matrix 75Cr3C2- 25 (NiCr) cermet has been one of the good choices for coating. In this study, we are discussing the HVOF (High Velocity Oxy Fuel) coating of 75Cr3C2-25(NiCr) on the low carbon steel substrate, IS 2062 grade B. The as coated samples were annealed at 600�C for 1 hour, 2hour and 3hours. The electrochemical tests were conducted for corrosion evaluation. Structural analysis was done by using X-Ray diffraction technique. Microstructure and thickness of the coating was studied using Scanning Electron Microscopy (SEM). Density measurement studies were done on as-coated and annealed coupons. � 2017 Elsevier Ltd.
Corrosion Behaviour and Characterization of Thermal Sprayed Coating of Nickel Chromium Cermet on Low Carbon Steel
(Elsevier Ltd, 2018) Amudha, A.; Shashikala, H.D.; Nagaraja, H.S.
Corrosion is the major problem faced by Navy, especially when pumps, ship impellers and other components have to work in harsh environments like sea water. Therefore, high corrosion resistant metal ceramic matrix 75Cr3C2- 25 (NiCr) cermet has been one of the good choices for coating. In this study, we are discussing the HVOF (High Velocity Oxy Fuel) coating of 75Cr3C2-25(NiCr) on the low carbon steel substrate, IS 2062 grade B. The as coated samples were annealed at 600Â°C for 1 hour, 2hour and 3hours. The electrochemical tests were conducted for corrosion evaluation. Structural analysis was done by using X-Ray diffraction technique. Microstructure and thickness of the coating was studied using Scanning Electron Microscopy (SEM). Density measurement studies were done on as-coated and annealed coupons. Â© 2017 Elsevier Ltd.
Corrosion protection of low-cost carbon steel with SS-309Mo and Inconel-625 bimetallic weld overlay
(Institute of Physics Publishing helen.craven@iop.org, 2019) Mudha, A.A.; Shashikala, H.D.; Nagaraja, H.S.
The dissimilar weld overlay coatings of components can lead to corrosion. In the present work, two different weld overlay layers (SS-309Mo and Inconel-625) are deposited on IS2062 grade B carbon steel, in order to avoid distortions and improve corrosion resistance. The microstructural investigations revealed that the intermediate layer SS-309Mo on carbon steel prevents the dilution by aiding crack-free weld overlay of Inconel-625 on the top. The corrosion behaviour of the coatings is studied using Linear Polarization Resistance and the Electrochemical Impedance Spectroscopy. The corrosion rate of the coatings decreased by two orders of magnitude compared to that of low carbon steel substrate. The corrosion rate of the deposited Inconel-625 along with intermediate SS-309Mo is 1.16×10-3 and is comparable to that of bare Inconel-625 (1.12×10-3 mmpy). Further, the immersion tests for 14 days show that, the depositions are stable with the formation of the passive film. ©2019 IOP Publishing Ltd.
Corrosion resistance and in-vitro bioactivity of BaO containing Na2O-CaO-P2O5 phosphate glass-ceramic coating prepared on 316 L, duplex stainless steel 2205 and Ti6Al4V
(Institute of Physics Publishing helen.craven@iop.org, 2018) Edathazhe, A.B.; Shashikala, H.D.
The phosphate glass with composition 11Na2O-15BaO-29CaO-45P2O5 was coated on biomedical implant materials such as stainless steel 316 L, duplex stainless steel (DSS) 2205 and Ti6Al4V alloy by thermal enamelling method. The structural properties and composition of glass coated substrates were studied by x-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive x-ray spectroscopy (EDS) analysis. The coatings were partially crystalline in nature with porous structure and pore size varied from micro to nanometer range. The polarization curve was obtained for uncoated and coated substrates from electrochemical corrosion test which was conducted at 37 °C in Hank's balanced salt solution (HBSS). The corrosion resistance of 316 L substrate increased after coating, whereas it decreased in case of DSS 2205 and Ti6Al4V. The XRD and SEM/EDS studies indicated the bioactive hydroxyapatite (HAp) layer formation on all the coated surfaces after electrochemical corrosion test, which improved the corrosion resistance. The observed electrochemical corrosion behavior can be explained based on protective HAp layer formation, composition and diffusion of ions on glass coated surfaces. The in-vitro bioactivity test was carried out at 37 °C in HBS solution for 14 days under static conditions for uncoated and coated substrates. pH and ion release rate measurements from the coated samples were conducted to substantiate the electrochemical corrosion test. The lower ion release rates of Na+ and Ca2+ from coated 316 L supported its higher electrochemical corrosion resistance among coated samples. Among the uncoated substrates, DSS showed higher electrochemical corrosion resistance. Amorphous calcium-phosphate (ACP) layer formation on all the coated substrates after in-vitro bioactivity test was confirmed by XRD, SEM/EDS and ion release measurements. The present work is a comparative study of corrosion resistance and bioactivity of glass coated and uncoated biomedical implants such as 316 L, DSS and Ti6Al4V. © 2018 IOP Publishing Ltd.
Density and Refractive Index Variation of CaF2 Added Borosilicate Glasses
(Springer, 2024) Raghuvanshi, V.; Shashikala, H.D.
The borosilicate glass series with general formula 30SiO2-35B2O3-(35-X) Na2O-XCaF2 (X = 0, 10, 15, and 20 mol%) were prepared using the conventional melt-quenching technique. This paper focuses on the change in physical properties of borosilicate glass with an increase in CaF2 concentration. X-ray diffraction confirmed the amorphous nature of the prepared glass samples. Density was measured using Archimedes principle, and other physical parameters like molar volume and oxygen packing density were calculated with measured density. The density increased with an increase in the concentration of CaF2. The refractive index and UV-Vis spectroscopy of the glass samples were studied. Parameters like dielectric constant, molar refraction, reflection loss, electronic polarizability, metallization factor, and other UV parameters were also calculated using this data. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Design and development of ITO/Ag/ITO spectral beam splitter coating for photovoltaic-thermoelectric hybrid systems
(Elsevier Ltd, 2017) Sibin, K.P.; Selvakumar, N.; Kumar, A.; Dey, A.; Sridhara, N.; Shashikala, H.D.; Sharma, A.K.; Barshilia, H.C.
ITO/Ag/ITO (IAI) multilayer coatings were designed for spectral beam splitter applications and these coatings were deposited on glass substrates by magnetron sputtering method. The thicknesses of the component layers, namely, Ag and ITO were varied to achieve high visible transmittance, high NIR-IR reflectance and optimum cut-off wavelength. The optimized ITO/Ag/ITO exhibits high visible transmittance (?88%) and high NIR-IR reflectance (>90%) with an optimum cut-off wavelength (?900 nm). A novel chemical etching method was used to improve the transmittance of the plain glass substrate. The optimized IAI multilayer coating deposited on single side etched glass substrate resulted in increase in transmittance (?91%), which is due to the nano-porous morphology of the etched glass substrate. The angular and polarization dependence studies of IAI multilayer coatings were also studied in detail. © 2016 Elsevier Ltd
Dissolution and in vitro bioactive properties of BaO added Na2O-CaO-P2O5 glasses
(Society of Glass Technology christine@glass.demon.co.uk, 2018) Edathazhe, A.B.; Shashikala, H.D.
Na2O-CaO-P2O5 glasses with different additions of BaO were subjected to dissolution tests in deionised water and in vitro bioactivity tests in phosphate buffer saline (PBS) as well as Hank's balanced salt (HBS) solution. Phosphate glasses of composition (26-x)Na2O-xBaO-29CaO-45P2O5 (x=0, 5, 10, 15 mol%) were prepared by melt-quenching. The dissolution characteristics of these glasses were studied in deionised water under static conditions based on BaO composition. The dissolution rate of the glasses in deionised water decreased with BaO content. The in vitro bioactivity tests were carried out in PBS and HBSS for 28 days under static conditions. The bioactivity of the samples was verified by XRD, SEM/EDS and FTIR techniques. Hydroxyapatite phases were formed on all the glass samples within seven days of immersion in HBSS and the bioactivity was found to improve with BaO content. The glasses without BaO and with 15 mol% BaO showed the hydroxyapatite phases within the immersion of 14 days in PBS whereas the glasses with 5 and 10 mol% BaO showed formation of amorphous hydroxyapatite phases. © 2018 Society of Glass Technology. All rights reserved.
Dissolution studies of Na2O-BaO-CaO-P2O5 glasses in deionized water under semi-dynamic conditions for bioactive applications
(2018) Edathazhe, A.B.; Shashikala, H.D.
The phosphate glasses of composition Na2O-CaO-P2O5 are widely accepted glass material for biomedical applications. The glass samples with composition (26-x)Na2O-xBaO-29CaO-45P2O5 (x = 0,5,10,15) are prepared at 1100�C by melt-quenching technique. In order to reduce the fast dissolution rate, which limits their application, BaO is added by reducing Na2O composition. The dissolution studies have been carried out in deionized water under semi-dynamic conditions at 37�C for 14 days. The properties are studied based on Barium composition and time of immersion. The samples are taken out at 24 hrs. intervals to carry out weight loss and pH measurements. The rates of cation (Na+ and Ca2+) release from the glass to the solution were found out using flame photometer. The release of orthophosphate (PO4 3-) anions is measured by UV-Visible spectrometer using phospho-molybdenum blue method. The weight losses linearly increase with time for all the compositions. The addition of barium decreases the weight loss in deionized water. The pH of the solutions varies with dissolution of ions. The dissolution rate has been found out from the slope of the weight loss vs time graph and it decreased with increase in barium content. � 2018 Elsevier Ltd. All rights reserved.
Dissolution studies of Na2O-BaO-CaO-P2O5 glasses in deionized water under semi-dynamic conditions for bioactive applications
(Elsevier Ltd, 2018) Edathazhe, A.B.; Shashikala, H.D.
The phosphate glasses of composition Na2O-CaO-P2O5 are widely accepted glass material for biomedical applications. The glass samples with composition (26-x)Na2O-xBaO-29CaO-45P2O5 (x = 0,5,10,15) are prepared at 1100Â°C by melt-quenching technique. In order to reduce the fast dissolution rate, which limits their application, BaO is added by reducing Na2O composition. The dissolution studies have been carried out in deionized water under semi-dynamic conditions at 37Â°C for 14 days. The properties are studied based on Barium composition and time of immersion. The samples are taken out at 24 hrs. intervals to carry out weight loss and pH measurements. The rates of cation (Na+ and Ca2+) release from the glass to the solution were found out using flame photometer. The release of orthophosphate (PO43-) anions is measured by UV-Visible spectrometer using phospho-molybdenum blue method. The weight losses linearly increase with time for all the compositions. The addition of barium decreases the weight loss in deionized water. The pH of the solutions varies with dissolution of ions. The dissolution rate has been found out from the slope of the weight loss vs time graph and it decreased with increase in barium content. Â© 2018 Elsevier Ltd. All rights reserved.
Effect of alkali earth oxides on hydroxy-carbonated apatite nano layer formation for sio2 –bao–cao–na2 o–p2o5 glass system
(Springer Science and Business Media Deutschland GmbH, 2017) Kiran, P.; Ramakrishna, V.; Shashikala, H.D.; Udayashankar, N.K.
Barium soda lime phosphosilicate [(58SiO2– (32-x)BaO–xCao–6Na2 O–4P2O5 (where x = 15, 20, 25 and 30 mol%)] samples were synthesised using conventional sol–gel method at 700 °C sintering temperature. Thermal, structural properties were studied using thermo gravimetric analysis and differential thermal analysis, X-ray diffraction, scanning electron microscopy, fourier transform infrared and Raman spectroscopy. Using Raman spectra non-bridging oxygen concentrations were estimated. The hydroxy-carbonated apatite (HCA) layer formation on samples was analysed for 7 days using simulated body fluid (SBF) soaked samples. The growth of HCA layers self-assembled on the sample surface was discussed as a function of NBO/BO ratio. Results indicated that the number of Ca2? ions released into SBF solution in dissolution process and weight loss of SB-treated samples vary with NBO/BO ratio. The changes in NBO/BO ratios were observed to be proportional to HCA forming ability of barium soda lime phosphosilicate glasses. © Springer. All rights reserved.
Effect of BaO addition on the structural and mechanical properties of soda lime phosphate glasses
(Elsevier Ltd, 2016) Edathazhe, A.; Shashikala, H.D.
The phosphate glasses of composition (26-x)Na2O-xBaO-29CaO-45P2O5 (x = 0,5,10,15 mol%) are prepared by melt-quenching technique. The variations in structural and mechanical properties are studied on glasses prepared at 1000, 1100 and 1200? C. The density of glasses increases with barium content for glasses prepared at different temperatures. The molar volume is nearly constant with compositional parameter. The amorphous nature of samples is confirmed by XRD. The calculated values of mass percentage of elements in the batch composition and EDS data are in a reasonable agreement. The FTIR spectra show that the main structural units in these glasses are Q1 and Q2 phosphate units. The frequency of the P[sbnd]O[sbnd]P band remains constant with barium substitution. The microhardness is measured using Vickers indentation method by applying 0.98 N for 10 s. The hardness and fracture toughness are independent of composition. The nature of crack formations is examined by SEM. The brittleness and crack length are correlated with plastic flow in the material. © 2016 Elsevier B.V.
Effect of BaO on thermal and mechanical properties of alkaline earth borosilicate glasses with and without Al2O3
(Elsevier B.V., 2019) Bhattacharya, S.; Shashikala, H.D.
BaO-CaO-Al2O3-SiO2 (BCAS) glass and their derivatives have gained extreme importance for their high endurance to elevated temperatures and suitability for various electrochemical applications. Two glass systems, one being 50 mol%[SiO2-B2O3]-xBaO-(45-x)CaO-5Al2O3 with x = 0, 10, 20, 25, 30, 35 and 40 mol%, represented as BCBSA and another without Al2O3 termed as BCBS, synthesized using melt quenching technique are considered here. The authors focus on the thermal and mechanical properties of these glasses. Reducing BaO concentrations improve the coefficient of thermal expansion (CTE/?) and other characteristic temperatures of glasses. Compacted glass pellets made of the water quenched frits show maximum shrinkage at 700 °C. Dilatometric analysis were conducted on compacts showing maximum shrinkage. CTE of these pellets are more than the bulk glasses. Glasses with low BaO concentrations exhibit high hardness and Young's modulus. Glasses bearing 20 mol% BaO, or even lesser, meet the thermal and mechanical properties required for high temperature sealants. © 2019 Elsevier B.V.
Effect of CaF2 addition on optical properties of barium phosphate glasses
(2014) Kumar, N.M.; Rao, G.V.; Akhila, B.E.; Shashikala, H.D.
Ternary barium phosphate glasses, (50-X)BaO-XCaF2-50P2O5 have been prepared by adding 0-10 mol% of CaF2 to binary barium phosphate glasses. The amorphous nature of the prepared glasses was confirmed by X-ray diffraction technique. The UV-Visible absorption spectra have been recorded, optical band gap energy Eopt and Urbach energy Etail were determined. Shift in Eopt and Etail with increase in concentration of CaF2 is noted. FTIR analysis was carried out to investigate the short and intermediate-range orders in glasses. Shift of (P-O-P) band to higher wave number with the substitution of BaO with CaF2 shows the shortening of the phosphate chains. Hardness and density of glass samples were measured and correlated with the composition of glasses. � 2014 AIP Publishing LLC.
Effect of CaF2 addition on optical properties of barium phosphate glasses
(American Institute of Physics Inc. subs@aip.org, 2014) Narayanan, N.M.; Venkateswara Rao, G.; Akhila, B.E.; Shashikala, H.D.
Ternary barium phosphate glasses, (50-X)BaO-XCaF2-50P2O5 have been prepared by adding 0-10 mol% of CaF2 to binary barium phosphate glasses. The amorphous nature of the prepared glasses was confirmed by X-ray diffraction technique. The UV-Visible absorption spectra have been recorded, optical band gap energy Eopt and Urbach energy Etail were determined. Shift in Eopt and Etail with increase in concentration of CaF2 is noted. FTIR analysis was carried out to investigate the short and intermediate-range orders in glasses. Shift of (P-O-P) band to higher wave number with the substitution of BaO with CaF2 shows the shortening of the phosphate chains. Hardness and density of glass samples were measured and correlated with the composition of glasses. Â© 2014 AIP Publishing LLC.