MEDIA EFFECTS ON THE KINETICS OF ANTHRACENE PHOTOOXIDATION IN POLYMERS

An improved quantitative analysis of the photochemical reaction of dip henylanthracene (DPA) in thin films of poly(ethyl methacrylate) (PEMA) is reported. This analysis confirms the previous suggestion (J.R. She ats, J. Phys. Chem., 94 (1990) 7194) that the rate of reaction between singlet oxygen and DPA decreases as the reaction proceeds, consistent with the hypothesis that the free volume is decreased by endoperoxide formation. For [DPA] almost-equal-to 30 wt.%, the rate constant decre ases by approximately 50% for complete conversion. The initial value i s 25-fold smaller than in fluid solution, and decreases slightly as [D PA] is increased.