Preparation and characterisation of high refractive index PbO–TiO2–TeO2 glass systems
Abstract
We describe the preparation and characterisation of high refractive index PbO–TiO2–TeO2 glass systems. Highly homogeneous glasses were obtained by agitating the oxide mixture during the melting process in an alumina crucible. The characterisation was performed by X-ray diffraction, density, dilatometry, Raman scattering, light absorption and linear refractive index measurements. The results show a change in the glass structure as the PbO content increases: the TeO4 trigonal bipyramids characteristic of TeO2 glasses transform into TeO3 trigonal pyramids. However, the measured refractive indices are almost independent of the glass composition. We show that third-order non-linear optical susceptibilities calculated from the measured refractive indices using Lines' theoretical model are also independent of the glass composition.