The kinetics of E' centers, introduced into silica by 4.7eV laser irradiation, were investigated by observing in situ their optical absorption band at 5.8eV. After exposure, the defects decayed due to reaction with diffusing molecular H of radiolytic origin. Hydrogen-related annealing was also active during exposure and competed, with photo-induced generation of the centers, until saturation was reached. The concentrations of E' and H2 at saturation were proportional, thus indicating that the UV-induced generation processes of the 2 species were related. The results were consistent with a model in which E ' and H were generated from a common precursor Si–H.

In situ Observation of the Generation and Annealing Kinetics of E' Centres Induced in Amorphous SiO2 by 4.7eV Laser Irradiation. F.Messina, M.Cannas: Journal of Physics - Condensed Matter, 2005, 17[25], 3837-42