Spur recombination and diffusion processes in pulse irradiated inorganic glasses

Abstract

Pulse radiolysis studies are carried out in pure and doped metaphosphate, borate, and silicate glasses in the range between 80 and 315 deg C. The observed decay patterns are shown to be due to the recombination of ions, holes, and electron centers, within spurs. The time dependence of the fraction of surviving radicals is in good agreement with the empirical expression F(t) = exp(k/sub s/ alpha ) erfc (k/sub s/t/ alpha )/sup 1/2 (where alpha is a constant and k/sub s/, is the diffusion controlled recombination rate constant) predicted by Rzad, et al., for systems undergoing spur recombination processes. Differences of several orders of magnitude among the diffusion coefficients of the various ions and centers explain the large variations in the rates of the corresponding diffusion-controlled electron-transfer reactions in glasses. The possibility of calculating relative diffusion coefficients ln glasses from the annihilation data is discussed. Results indicate that the diffusion coefficient of Mn/sup 3+/ is (3 plus or minus 1) x 10/sup 3/ higher than that of Cd/sup +/ in the temperature range 80 to 240 deg C. (auth)