RADIATION-INDUCED DEFECTS IN GLASSES - ORIGIN OF POWER-LAW DEPENDENCE OF CONCENTRATION ON DOSE

We propose, and verify in the case of a Ge-doped-silica-core optical fiber, a general explanation for the power-law dependencies on dose frequently observed for the concentrations of radiation-induced defect centers in insulating glasses. This insight permits detailed prediction of the postirradiation recovery curves, given just the empirical exponent of the power law, 0 < f < 1, and the experimental irradiation time, t(irrad). The time constant of the recovery is given by t(irrad)/(1 - f), independent of the order of the kinetics. We establish a microscopic model (radiolytic oxygen molecules) for the gamma-ray-induced absorption at 1.3 mum in our test fibers and infer a diffusion-limited bimolecular recombination process.