Raman characterizations and structural properties of the binary TeO2-Wo_3/ TeO₂-CdF₂ and ternary TeO₂-CdF₂-Wo₃ glasses

The Raman spectroscopy technique was used to characterize the microstructure and the crystallization properties of the as-cast and heat-treated binary TeO₂-WO₃, TeO₂-CdF₂ and ternary TeO₂-CdF₂-WO₃ glasses and glass ceramics. The results were compared with those obtained by using the X-ray diffraction technique. The effect of the WO₃ and CdF₂ contents on the TeO₂ glass network and the intensity ratios of the deconvoluted Raman peaks were determined. The shifts in the Raman band wavenumbers and the intensity values for each band were investigated. The Raman results indicated that the glasses were mainly formed by the [TeO₄] and [TeO₃] units. The [TeO₄] units convert to [TeO₃] units with the addition of WO₃ and CdF₂ into tellurite glasses. All the crystalline phases such as α-TeO₂, δ-TeO₂ and γ-TeO₂ existing in the TeO₂-WO₃, TeO₂-CdF₂ and TeO₂-WO₃-CdF₂ glasses were determined. The transformation of the metastable γ-TeO₂ phase into stable α-TeO₂ was observed for the (1 - x)TeO2-XWO3 (where x = 0.15, 0.20, 0.25), 0.90Te2-0.10CdF2, the 0.85TeO2-0.10CdF2-0.05WO3 and 0.80TeO₂-0.10CdF₂-0.10WO₃ glasses, and the transformation of the metastable δ-TeO₂ phase into the stable α-TeO₂ was also observed for the TeO₂-CdF₂-WO₃ glass system. In addition, an unidentified phase formation, labeled e, was determined.