Optical and Thermal Properties of Some Tellurite Glasses

Tellurite glasses in the form (95-X) TEO 2-5NB 2O 5-XTIO 2, X= 5.0, 7.5, 10.0 and 12.5 mol % have been successfully prepared by the melt quenching technique. Density ρ and molar volume V have been measured. UV-Visible absorption spectra for the presented ternary tellurite glass systems have been measured in the wavelength range 200-850 nm. The optical band gap, E g, and refractive index, n, of the presented glass systems have been calculated by using the derivation absorption spectrum fitting (DASF) and absorption spectrum fitting (ASF) methods. Also, Urbach’s energy, ΔE for tellurite glass systems was obtained using the absorption spectrum fitting (ASF) method. Comparison between both methods has been presented. Differential thermal analysis (DTA) for the prepared glasses with systematic heating rate 10°C/min has been carried out. The glass transition temperature, T g, onset crystallization temperature, T c, melting temperature, T m, glass stability range, S, and glass factor, K g, of the present glasses have been measured. The average cross-link density, ˉn c, number of bonds per unit volume, n b, and average stretching force constant, Fˉ, have been calculated.