PHOTOINDUCED DESTRUCTION OF POLAR STRUCTURE IN DYE-PENDANT POLYMERS STUDIED BY 2ND-HARMONIC GENERATION

Second-harmonic generation (SHG) was observed in polymer/azo dye syste ms during light irradiation. The SHG activity produced by poling was c ompletely lost by partial trans-cis isomerization in dye-pendant syste ms, while this phenomenon was observed less in a dye-dispersed system. Taking account of the observations in various polymer matrices, we co ncluded that the destructive process of the poled structure is amplifi ed through a movement of the polymer main chain induced by the partial photoisomerization of chromophores.