Spectroscopic and luminescence studies of thulium doped strontium borate glass

Abstract Un-doped as well as Tm doped strontium borate glasses were prepared and characterized by different spectroscopic techniques. 11 B MAS-NMR studies on the glass samples have shown the presence of BO 3 structural units in addition to the tetrahedrally coordinated BO 4 structural units confirming glass formation. Optical absorption and photoluminescence studies of these samples showed stabilization of thulium as Tm 3+ ions in the virgin sample, while, on γ-irradiation, partial reduction to Tm 2+ was observed. EPR investigations of virgin and γ-irradiated samples showed the presence of BO 3 2 - centered radicals in the latter samples only. TSL studies of γ-irradiated Tm doped strontium borate glass showed two glow peaks around 423 and 528 K. Tm 3+ was identified as the luminescent center from spectral studies. Temperature dependence studies of EPR spectra have shown the thermal destruction of BO 3 2 - radical ion to be associated with the TSL glow peak at 423 K. Based on these investigations, the mechanism for the processes occurring during γ-irradiation and subsequent thermal treatment is proposed.