PREPARATION AND CHARACTERIZATION OF HIGH REFRACTIVE-INDEX PHO-TIO2-TEO2 GLASS SYSTEMS

We describe the predaration and characterisation of high refractive in dex PbO-TiO2-TeO2 glass systems. Highly homogeneous glasses were obtai ned by agitating the oxide mixture during the melting process in an al umina crucible. The characterisation was performed by X-ray diffractio n, 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 TeO4 glasses transform into TeO, trigonal pyramids. However, the measured refractive indices are almost independent of the glass composition. We show that third-order non-linear optical suscep tibilities calculated from the measured refractive indices using Lines ' theoretical model are also independent of the glass composition.