STUDIES OF OXYGEN DIFFUSION IN POLY(STYRENE-CO-1-NAPHTHYL METHACRYLATE) BY PHOSPHORESCENCE QUENCHING

Measurements of oxygen diffusion in naphthalene-labeled polystyrene films were made at cryogenic temperatures by observations of the kinetics of quenching of naphthalene phosphorescence. Values of the diffusion coefficient D ranged from 3.3 x 10(-11) to 2.8 X 10(-7) cm2 s-1 at -104 and +23-degrees-C, respectively. The activation energy for diffusion was 7.1 kcal mol-1, which is similar to that observed above room temperature. Static measurements employing the Stern-Volmer equation to determine k(q) gave comparable values only if k(q) = k(D)/9. Theoretical and experimental justifications for this relation are discussed.