Temperature dependent photoinduced change of third harmonic generation in azo copolymer thin films

Abstract

Temperature effect on photoinduced third harmonic generation (THG) variation of an azo copolymer and an azo guest-host polymer is studied at two different temperatures. At higher temperature, both angular hole burning (AHB) and molecule angular redistribution (AR) motions are smaller due to the decrease of cis-trans thermal relaxation time and cis population. Smaller photoinduced THG change is observed in both samples at higher temperature. THG recovery experiment results show copolymer thin films pumped at high temperature have the best photoinduced THG variation stability after turning off the pump beam.