Polyethylene imines having 4-methoxyazobenezene group through methylene spacer groups (PEI6M) were synthesized and their photochemical, thermooptical as well as photoorientational behavior were investigated. PEI6M films showed high dichroism and order parameter values after annealing and developed out-of-plane order. Multiply-layered films exhibited reflection band and reflection band was almost disappeared by annealing the films at 80 degrees C. In addition reflection band was again observed by UV light irradiation because of reorientation of azobenzene groups from out-of-plane order to random state. The photochemical control of molecular orientation of PEI6M between random state and out-of-plane structures were achieved by combination of thermal and photochemical processes.