Investigation of surface relief gratings on azo-copolyimide films using atomic force microscopy

Azo-copolyimide films were explored regarding the surface relief gratings formation under the action of pulsatory laser irradiation. The azo-copolyimides have been synthesized by the polycondensation reaction of benzophenonetetracarboxylic dianhydride and a mixture of two diamines, one of which contains substituted phenyl groups and the other one contains two pendent substituted azobenzene group, taken in the molar ratio 3 : 1, respectively. Atomic force microscopy was used to investigate the surface relief gratings characteristics in different conditions and for different structures of the azo-copolyimide films.