Study On The Photoinduced Anisotropy In Azo-Containing Polymer Films

Azo polymers have attracted much attention for their potential applications in optoelectronics and optical storage because of their special characters in photophysics and photochemistry. This paper concentrates on the photoinduced anisotropy characters of azo containing polymers. Based on the photoinduced isomerization and reorientation of azo chromophores, the photoinduced birefringence, polarization hologram and surface relief gratings are investigated. First of all, we focus on the temperature dependence of photoinduced anisotropy in azo polymers. The photoinduced birefringence in azo polymers is investigated at different temperatures between -20°C to 50°C. There is a peak value of photoinduced birefringence in the temperature dependence of the photoinduced birefringence under a certain pumping intensity. With the pumping light in 90 mW/cm2, the peak value of the photoinduced birefringence appeared at about 0°C. A competition between the photoinduced reorientation and the thermal random motion is employed to explain this temperature dependence. And this competition mechanism is proved by a theoretical simulation.Secondly, polarization holographic recording is investigated in a...