Luminescence and microstructure of Sm2+ ions reduced by x-ray irradiation in Li2O-SrO-B2O3 glass

Sm3+-doped Li2O-SrO-B2O3 glass sample was prepared by the conventional melt quenching method in air atmosphere. Sm2+ ions in this borate glass were obtained by x-ray irradiation reduction method. The as-prepared and x-ray-irradiated samples were investigated by photoluminescence spectrum and decay curve measurements. The dependence of Sm2+ luminescence intensity on the x-ray irradiation time was investigated. It is found that the conversion of Sm3+-> Sm2+ after x-ray irradiation is efficient in this borate glass. Photostability of Sm2+ ions was evaluated by the photobleaching method. Furthermore, the induced optical absorption spectrum measurement after x-ray irradiation was performed. Thermoluminescence above room temperature was also studied after x-ray irradiation. The different kinds of defect structures and the reduction mechanism of Sm2+ ions in this borate glass were discussed. The microstructure of Sm ions in the Li2O-SrO-B2O3 glass was suggested. The proposed microstructure would be helpful to understand the reduction mechanism of Sm2+ ion in borate glasses. (C) 2008 American Institute of Physics.