FT-IR and Raman spectroscopic studies of ZnF2–ZnO–As2O3–TeO2 glasses

The effect of fluorine substitution on the spectral properties of the xZnF2–(20-x)ZnO–40As2O3–40TeO2 (x = 0, 4, 8, 12, 16 and 20 mol%) glass system was investigated by FTIR and Raman spectroscopies. The results demonstrate that TeO4 and TeO3 were among the primary structural units in the investigated glasses in addition to As2O3 pyramids and ZnO4 structural units. The addition of fluorine results in the reduction of TeOTe linkage due to a gradual transformation of trigonal bipyramidal TeO4 through TeO3+1 to trigonal pyramidal TeO3, which decreases the connectivity of the tellurite glass former network. The theoretical optical basicity of the studied glasses decreases with increasing ZnF2 content.