A NOVEL IMAGING-SYSTEM BY DYE-SENSITIZED PHOTOOXIDATION OF OXAZOLE GROUPS ATTACHED TO A POLYMER BACKBONE .3. EFFECT OF THE SENSITIZER ON PHOTOOXIDATION IN THIN-FILMS

Oxazole rings attached to a copolymer backbone, which was composed of 2-[3-(methacryloyloxy)-propyl]-4,5-diphenyl-1,3-oxazole and N-isopropylacrylamide, were transformed efficiently to the corresponding N,N-dibenzoylcarboxamide derivatives in a thin film by photooxidation using various dyes as photosensitizers. This photoinduced transformation was found to be applicable to a panchromatic photoresist with positive tone by development with an aqueous solution of amines to dissolve the exposed areas of the film. The photooxidation had the quantum efficiency for generation of singlet oxygen in the range 0.2-0.7 depending upon the sensitizers used in the system. The conversion showed a maximal value when the average distance between the oxazole rings and sensitizer molecules was about 30 angstrom.