Temperature Dependence of Photoinduced Birefringence in an Azobenzene Polymer

The photoinduced birefringence in an azobenzene polymer is investigated at different temperatures between −20°C to 50°C. It is found that there is a peak value of photoinduced birefringence in the temperature dependence of the photoinduced birefringence under a certain pumping intensity. With the pump light in 90 mW/cm2, the peak value of the photoinduced birefringence appeared at about 0°C. The effect of temperature on the photoinduced birefringence is discussed using the competition mechanism between the photoinduced reorientation and the thermal random motion.