OPTICAL PROPERTIES OF BORO-GERMANATE GLASS SYSTEMS
Abstract
Three samples of boro-germanate glass system (GeO2–B2O3) were prepared by cooling the melt from 1473°K in the compositional series containing 40, 35 and 30 mol% B2O3. For these glasses the optical absorbance, % transmission, optical band gap, relative permittivity (εr), index of refraction (n) and index of dispersion (Abbe No., Vd) have been determined. The position of the absorption edge and hence the optical band gap (Eopt) was found to depend on glass composition. The absorption edge was attributed to indirect transitions. The values of Eopt and nd were observed to decrease with increasing B2O3 content while εr and Vd increased with increasing B2O3 content.