The effect of the molecular structure of the chromophore on the photorefractive properties of the polymer systems with low glass transition temperatures

Abstract

Seven chromophores with different dipole moments and polarizability anisotropies were synthesized by varying conjugation bridges, such as polyene, thiophene, indole, and benzene combined with strong electron-donor and electron-acceptor groups. The birefringence of photorefractive materials containing 30 wt% of chromophore was observed to be in the range of 0.45 × 10⁻³ to 5.0 × 10⁻³ at an electric field of 70 V µm⁻¹, depending on the chromophore structure. The photorefractive material containing a polyene-based chromophore exhibited the highest photorefractive property, followed by those containing thiophene-based, benzene-based and indole-based chromophores. It was observed that, within material systems used in this study, photorefractive properties of guest–host systems were linearly proportional to the orientational birefringence.