Abstract
The optical absorption is studied as a function of γ-irradiation dose and composition for a series of magnesium phosphate glasses. The optical absorption spectra were measured in the wavelength range from 200 to 1100 nm at different γ-doses in the range from 0.2 to 1.0 Mard. The obtained results are analysed assuming optical absorption by indirect transitions. Values of Λ0 the absorption band edge wavelength, the optical energy gap and the width of the band tail (Eopt, and ΔE) are determined. They are found to be γ-irradiation dependent for γ-dose values up to 1.0 Mard. It was found from these parameters that the present glass system can be divided into two distinct compositional regions: below and above 35 mole % MgO.