Synthesis, characterization and determination of third-order optical nonlinearity by cw z-scan technique of novel thiobarbituric acid derivative dyes

Abstract

Donor acceptor chromophores were prepared by Knovenagel reaction of 1,3-diethyl-2-thiobarbituric acid with corresponding aldehydes in ethanol using pyridine as catalyst. The structures of newly synthesized compounds were evaluated by FT-IR, 1H NMR, 13C NMR, MS spectroscopy and purity of the compounds were confirmed by elemental analyses. The nonlinear refractive index n2 and nonlinear absorption coefficient β are measured for these dyes using the closed and open aperture z-scan technique with a cw He–Ne laser at 632.8nm. These values are found to be high and linearly dependent on the concentration.