Photo-induced behavior of polymethacrylate polymer, with cyano azobenzene side group, was studied.
The photoisomerization process occurs in cyano azo polymer, by illumination of a film with polarized
and unpolarized light. The illumination of the polymer film with light results in color change, the color
of film gets darker. This is in opposition to common azo polymers in which the result of illumination
is a photo-bleaching. Study of spectrum changes of a dilute polymer solution shows that the color change
under pump beam illumination is not due to interaction between dye molecules. Time evaluation of
probe beam absorption induced by Ar+ laser pump beam shows the fast change in population of isomers
at higher light powers. Light induced birefringence (LIB) experiments with high power pump beams
shows uncommon new features. A high long-term stability of LIB is demonstrated when the polymer film
is kept in the dark. Not only a circular polarized light cannot erase the birefringence but it also induces
anisotropy in polymer film. It appears that this is relevant of a phase transition in the polymer film.
