Some physical properties of gamma-irradiated alkali-silicate glasses

The effects of gamma-irradiation on absorption spectra, density, refractive index and electrical conductivity of glasses containing different impurities substituting for silica have been measured for absorbed doses in the range 5.4 - 54 KGy. The observed changes in the measured parameters, is explained in terms of the irradiation-induced diffusion of lattice atoms, exchange of lattice positions and displacement of interstitial vacancy pairs. The results are also discussed in light of the known effects of radiation in the rupture and reformation of bonds and prevention of small scale atomic rearrangements. The optical energy gap (Eopt) was found to decrease with the increase of the radiation dose, and it is suggested that the mechanism of optical transition is forbidden by indirect transition. (Author)