The photo-oxidation reaction of poly (styrene-sulfone)-a novel positive deep UV photoresist including film and solution has been studied by fluorescence spectra.The fluorescence intensity of poly (styrene-sulfone) decreased gradually with the duration of exposure. This phenomena was also observed when a trace amount of aromatic hydrogen peroxide or carbonyl compounds introduced to poly (styrene-sulfone) which was without irradiation. It indicated that the quenching of the fluorescence of poly (styrene-sulfone) after irradiation was related with the formation of hydrogen peroxide or carbonyl group during the process of photooxidation. This method

evidently

can be used for studying the starting period of the photo-oxidation of polymers. The mechanism of photooxidation of poly(styrene-sulfone) has been discussed on the basis of this results.