Interaction of gamma ray with some alkali-borate glasses containing iron

The change of optical absorption of some irradiated alkali borate glasses containing iron has been studied by varying gamma-ray dose or the alkali oxide content. To separate the absorption due to iron from the intrinsic absorption, blank glasses were prepared and measured. The results showed that the induced absorption spectra exhibited changes with the radiation dose and chemical composition of the glass. A resolution of the observed absorption spectra shows that three bands are induced with their maxima at locations as follows: first split-band with peaks at 350-380 nm, second split-band with maxima at 400-420 nm and third band at 580 nm. The response of the glasses to gamma-ray irradiation is related to the formation of defects and hence the colour centres, to the approach of saturation after a certain gamma dose, and also to the possible photochemical effect of the transition metal in the glass. The decay in band intensity which is noticed by thermal bleaching was also studied. (author). 24 r efs., 9 figs