Shettigar, S.Umesh, G.Poornesh, P.Murthy, Y.L.N.2020-03-302020-03-302007ICTON-MW'07 - International Conference on Transparent Optical Networks "Mediterranean Winter" 2007 - Conference Proceedings, 2007, Vol., , pp.-https://idr.nitk.ac.in/handle/123456789/7865We report the investigation of third order optical nonlinearity of 2,4,6-tri-(p-hyptoyoxylphenyl) pyrilium tetraborate doped PMMA using nanosecond laser pulses at 532nm wavelength by employing Z-Scan technique. To see the effect of polymer host, the results have been compared with the pure dopant. The material shows a large negative nonlinearity with real and imaginary parts of X(3) are - 3.31�10-14esu and 0.73�10 -14esu respectively. Excited state absorption cross-section is found to be 3.41�10-48 cm4.s/photon in PMMA host. The magnitude of third order nonlinear parameters increases when the compound is doped into PMMA matrix because of change in the conformation of chain geometry as a result of charge transfer processes. The values are comparable with a best known nonlinear liquid crystal molecule namely, 4-cyano-4'-n-pentylbiphenyl in the nematic phase. Hence, these molecules can be suitably used as nonlinear optical materials in PMMA matrix for device applications. � 2007 IEEE.Book chapter