Study of spectroscopic and thermal characterization of TeO₂-Ga₂O₃ oxyfluoride (TGOF) glasses and glass-ceramics activated by Pr³⁺ ions. The role of phonons

The glasses based on TeO₂-Ga₂O₃ system as a promising group of heavy metal oxide glasses have been subject of great attention in the aspect of optoelectronics applications because of good transparency in the mid-infrared up to 6–7 µm and the possibility to incorporate a large amount of RE ions. The paper presents thermal stability, the UV–VIS and IR transmission and luminescence spectroscopy of the gallium-tellurite oxyfluoride glass. The base gallium-tellurite glass 0.74TeO₂·0.15Ga₂O₃ was modified by addition of 11 mol% BaF₂ and 1 mol% Pr₆O₁₁. DTA/DSC data showed that the glasses are characterized by the multi-stage crystallization. The luminescence spectra have been registered at various temperatures and resulting characteristics allowed to draw conclusions on the role of phonons in their evolution at different temperatures. To interpretations a kinetic analysis and the Bose-Einstein statistics were employed.