Pseudo Photorefractivity and Structural Correlation for Polyacrylate Containing Thioxanthene Moiety Doped with EO Active Chromophores

Abstract

Pseudo photorefractivity and structural correlation was investigated for the composites consisting of polyacrylate containing electron accepting thioxanthene (TH) moiety and electro-optical (EO) chromophore via a two beam coupling experiment. Tuning of electron accepting nature was achieved by the chemical modification of carbonyl group in 9-oxo-9 H- thioxanthene-10,10-dioxide unit. EO chromophores with various structural characteristics were examined. It is revealed that the stronger was the electron accepting nature,the lower was pseudo photorefractivity, and the composites with EO chromophore exhibiting photoisomerization showed the higher coupling gains. It is considered that excessive charge transfer interaction impedes the photoalignment followed by the migration of EO chromophore, and cis-trans photoisomerization is an essential step to create the refractive index grating phase-shifted with the interference pattern.