Optical, physical and structural studies of boro-zinc tellurite glasses

To investigate the modification effect of the modifier ZnO on boro-tellurite glass, a series of glasses with compositions 50B2O3–(50−x)ZnO–xTeO2 have been prepared by conventional melt quenching technique. Amorphous nature of the samples was confirmed through X-ray diffraction technique. Optical absorption and IR structural studies are carried out on the glass system. The optical absorption studies revealed that the cutoff wavelength increases while optical band gap (Eopt) and Urbach energy decreases with an increase of ZnO content. Refractive index evaluated from Eopt was found to increase with an increase of ZnO content. The compositional dependence of different physical parameters such as density, molar volume, oxygen packing density, optical basicity, have been analyzed and discussed. The IR studies showed that the structure of glass consists of TeO4, TeO3/TeO3+1, BO3, BO4 and ZnO4 units.

Research highlights
► Novel boro-zinc tellurite ternary glasses that can compete with boro-tellurite and zinc tellurite glasses are successfully prepared.
► Boro-zinc tellurite ternary glasses are of higher refractive index compared with zinc tellurite glasses.
► Optical, physical and structural properties of the novel ternary glass system are explained.
► At 30 mol% of ZnO, TeO4 is replaced by ZnO4 indicating the presence of ZnO4 network.