This investigation studied the orientation behavior of one kind of epoxy-based azo polymers (BP-AZ-CA) containing carboxyl as the electron-withdrawing group on the azobenzene unit with different degree of functionalization (DF).The orientation behavior was studied by photoinduced birefringence measurements and polarized infrared spectroscopy.The effect of degree of functionalizaiton on the orientation behavior of azo chromophores and polymer main-chains of BP-AZ-CA were observed.The results show that the orientation rate

relaxation rate and saturated orientation level of BP-AZ-CA are significantly influenced by the degree of functionalization.With the increase of DF of BP-AZ-CA

the orientation rate of both azo chromophores and polymer main-chains decrease.The influence of the DF on the orientation rate of polymer main-chains becomes weak when the DF of BP-AZ-CA is higher than 69%.With the increase of DF of BP-AZ-CA

the relaxation rate of both azo chromophores and polymer main-chains decrease

indicating the increasing molecular interaction has positive impact on the stability of the orientation of BP-AZ-CA induced by exciting polarized laser.The saturated orientation level of azo chromophores and polymer main-chains increases with the DF increase

but the DF has a more significant influence on azo chromophores than on polymer main-chains.The hydrogen-bond strength also plays an important role in enhancing the orientation behavior of BP-AZ-CA

increasing with the increase of DF.