Photoinduced Destruction of Polar Structure in Dye-Pendant Polymers Studied by Second-Harmonic Generation

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