New soluble polyimides containing the hydroxylic group. II: Polymers substituted with Disperse Red 1

A series of aromatic polyimides synthesized from various diamidedianhydrides and 2,4-diamino-phenol dihydrochloride were substituted with 4-[N-ethyl-N-(2-hydroxyethyl)]amino-4'-nitro-azobenzene (Disperse Red 1) via the Mitsunobu reaction. The content of the chromophore in the polyimides has been determined by UV-Vis spectroscopy. The influence of the polyimide structure on the ability for the introduction of the chromophore into the polymers was investigated. Different conditions of the Mitsunobu reaction have enabled the synthesis of polyimides with various contents of DR 1. The induction of optical anisotropy in films of the photochromic polymers was studied by irradiating with the linearly polarized light of an Ar+ laser (488 nm). A dichroism up to 0.2 was induced depending on the content of the push-pull substituted azobenzene side group in these polyimides.