Influence of Sm₂O₃ on the crystallization and luminescence properties of boroaluminosilicate glasses

Sm₂O₃-doped SiO₂-B₂O₃-Al₂O₃-BaO glasses were prepared by melting method in order to study the influence of Sm₂O₃ on the crystallization behavior and luminescence properties. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy were used to characterize the rare earth glasses and the crystalline phases after heat-treatment. The course of phase separation and devitrification of the glasses were also investigated. The results show that the thermal stability of the glasses decreases with the increase of content of Sm₂O₃. The crystalline phase changed from SmAl_2.07(B₄O₁₀)O_0.6 to SmBO₃. Divalent Sm²⁺ ions were detected in the crystallization product after heat-treatment. The valence transformation from Sm³⁺ to Sm²⁺ in the crystal suggests the samarium atoms entering the barium sites. The charge carried in vacancy defect induced by the substitution led to the partial reduction process. The reduction of Sm³⁺ ions was promoted by the increasing of Sm₂O₃ content or the extending of heat-treated holding time in boroaluminosilicate glass.