Characterization of oxyfluorotellurite glasses with TeO2–Li2O–ZnO–LiF composition

Abstract

Oxyfluorotellurite glasses in the form of 60TeO 2 –(15–x)Li 2 O–25ZnO–xLiF, 65TeO 2 –(15–x)Li 2 O–20ZnO–xLiF (with x = 0, 5, 10, and 15 in mol %), and 65TeO 2 (20–x)Li 2 O–15ZnO–xLiF (x = 0, 5, 10, 15, and 20 in mol %) have been synthesized. The amorphous state of the samples was assessed using X-ray diffraction (XRD). Density, molar volume, and oxygen packing density (OPD) were measured. The thermal properties were analyzed from room temperature to 873 K using a differential scanning calorimeter (DSC). The structural and optical properties were investigated using Fourier-transform infrared (FTIR), Raman, and ultraviolet–visible (UV–Vis) spectroscopies. The results demonstrated that the OPD values decreased with increasing LiF content, and this decrease can be attributed to a decrease in the total oxygen number. The structural characterization revealed that the addition of LiF reinforces the vitreous network causing the formation of F–Te–O bonds within a more connected network. In addition, increasing the LiF content improved the glass’s thermal properties, with a decrease in the glass transition temperature and an increase in thermal stability, which facilitates the glass manufacturing process. However, this feature is dependent on ZnO concentration.