New tellurite glasses and crystalline phases in the Bi2O3–CaO–TeO2 system: Synthesis and characterization

Tellurite glasses containing calcium and bismuth oxides have been prepared at 800 °C and investigated by X-ray diffraction, DSC, IR and Raman spectroscopy. The crystalline phases of glasses in TeO2–CaO revealed γTeO2 phase which transforms into the stable αTeO2 phase up to 500 °C. IR and Raman studies show the transition of TeO4, TeO3+1 and TeO3 units with increasing CaO content. The value of refractive index and density of glasses have been measured. The investigation in the system using XRD reveals new phases.