Optical characterization of xTiO(2)-(60-x)SiO2-40Na(2)O glasses: II. Absorption edge, Fermi level, electronic polarizability and optical basicity

Abstract

In the present work different optical properties of xTiO2-(60 - x)SiO2-40Na2O (wt%) optical glasses are determined. The characterization is done over a wide energy range, 0.41-6.2 eV. The refractive index and the extinction coefficient data are used to measure the absorption coefficient of the different glass compositions. Studying the UV-absorption edge, both direct and indirect allowed transitions with their optical energy gaps are carried out. In the same time, the Urbach energy is evaluated. From the extinction coefficient data, the Fermi energy of the glasses is calculated. The molar refraction, electronic polarizability and the optical basicity are obtained using the measured glass refractive indices. © 2005 Elsevier B.V. All rights reserved.