A carbazole-based photorefractive polyphosphazene prepared via post-azo-coupling reaction

A carbazole-based photorefractive polyphosphazene was prepared via post-azo-coupling reaction. The polymer shows a low glass transition temperature of 50 °C, and has an excellent solubility in common organic solvents, which can easily be fabricated into an optically transparent film with long-term stability. The nonlinear optical effects, including two-beam-coupling and four-wave-mixing, were studied at 633 nm under room temperature. A gain coefficient of 79 cm−1 and a diffraction efficiency of 18% were observed at zero external electric field without any added plasticizer or sensitizer.