Gamma ray interaction with lithium borate glasses containing WO₃

Abstract

471-480Glasses from the system of undoped lithium diborate and WO3-doped were synthesized by the usual melting and annealing techniques. UV-visible absorption spectra of the prepared sample were measured before and after successive gamma irradiation. Undoped glass reveals strong UV absorption spectrum which is related to the presence of unavoidable trace iron impurity. The presence of tungsten ions in this glass system is observed to impart no colour or marked changes in the absorption spectrum of the host glass suggesting the presence of tungsten ions mostly as W6+ species. Gamma irradiation produces extended induced bands in the UV-visible regions in the undoped and WO3-doped glasses. These induced bands are related to the presence of intrinsic defects already present in the host lithium diborate glass and extrinsic defects due to the presence of both trace iron impurity and tungsten ions. Infrared absorption spectra reveal specific vibrational bands due to characteristic borate network beside modifier lithium ions (Li+) and tungsten groups. Raman spectra confirm the IR results regarding the presence of tungsten ions mainly as WO6 groups due to the oxidizing nature of the host glass. Tungsten ions are seen to cause shielding or retardation of the growth of the induced bands by gamma irradiation