Structural influence of aluminium, gallium and indium metal oxides by means of dielectric and spectroscopic properties of CaO–Sb2O3–B2O3 glass system

Dielectric constant (ɛ′), loss (tan δ), ac conductivity (σ) of CaO–Sb2O3–B2O3:M2O3 (Al2O3, Ga2O3 and In2O3) glasses with varying concentrations of M2O3 (0–5 mol%), were measured as a function of frequency and temperature over moderately wide ranges. The analysis of results of these studies along with IR, Raman and optical absorption spectra and also DTA studies indicated that in the concentration ranges, 0 ≤ Al2O3 ≤ 4, 0 ≤ Ga2O3 ≤ 2 and 1 ≤ In2O3 ≤ 5, Al3+, Ga3+ ions occupy tetrahedral positions whereas In3+ ions take up octahedral substitutional positions, cross-link with the other structural units in the glass network and increase the rigidity of the glass network.