Radiation defects in alkaline-earth silicate glasses were studied by using electron spin resonance and optical spectroscopic techniques. New relationships between the results arising from these methods were deduced by varying the glass composition, isochronally annealing the irradiated samples, optically bleaching the irradiated samples and varying the γ-ray dose. It was found that O hole centres were mainly responsible for a radiation-induced absorption in the visible part of the optical spectrum. Previously ignored electron centres, with broad and asymmetrical electron spin resonances (g = 1.955), contributed to the optical spectra (200 to 2000nm) to a small extent. It was suggested that they were due to electrons which were trapped on small aggregates of alkaline-earth ions. The radiation-induced re-charging of incorporated Fe3+ ions was also revealed by optical and electron spin resonance spectroscopy. The Fe3+ ions acted as electron traps which formed not only Fe2+, but also (Fe3+)- species which might have been responsible for an absorption band at 300nm.

Complementarity of ESR and Optical Absorption of γ-Irradiated Silicate Glasses. J.Bartoll, M.Nofz, R.Stosser: Physics and Chemistry of Glasses, 2000, 41[3], 140-9