Hegde, P.K.Vasudeva Adhikari, A.V.Manjunatha, M.G.Suchand Sandeep, C.S.Philip, R.2026-02-052010Journal of Applied Polymer Science, 2010, 117, 5, pp. 2641-2650218995https://doi.org/10.1002/app.30926https://idr.nitk.ac.in/handle/123456789/27413Three new donor-acceptor type poly{2,2 1-(3,4-dialkoxythiophene- 2,5-diyl)bis[5-(2-thienyl)-1,3,4-oxadiazole]}s (P1, P2, and P3) were synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. The polymerization was carried out using chemical polymerization technique. The optical and charge-transporting properties of the polymers were investigated by UV-visible, fluorescence emission spectroscopic and cyclic voltammetric studies. The polymers showed bluish-green fluorescence in solutions. The electrochemical band gaps were determined to be 2.03, 2.09, and 2.17 eV for P1, P2, and P3, respectively. The nonlinear optical properties of new polymers were investigated at 532 nm using single beam Z-scan and degenerate four-wave mixing (DFWM) techniques with nanosecond laser pulses. The polymers exhibited strong optical limiting behavior due to "effective" three-photon absorption. Values of the effective three-photon absorption (3PA) coefficients, thirdorder nonlinear susceptibilities (? (3)), and figures (F) of merit were calculated. © 2010 Wiley Periodicals, Inc.3,4-dialkoxythiopheneBand gapsChemical polymerizationDegenerate four-wave mixingDiethyl oxalatesDonor-acceptorsFluorescence emissionGreen fluorescenceMultistep reactionsNanosecond laser pulseNon-linear optical propertiesNonlinear optical studiesOptical limiting behaviorOxadiazolesSingle beamThienylThiodiglycolic acidThird-order nonlinear susceptibilityThree photon absorptionThree-photon absorption (3PA)UV-visibleVoltammetric studiesAbsorptionFluorescenceFour wave mixingLight absorptionMultiphoton processesOptical propertiesPhotonsPolymerizationPulsed laser applicationsBiodegradable polymerschemical compositionfluorescencelaserpolymerizationsynthesistransport process