Refractive index calculation using the structural properties of $La4Ti9O24$ glass Available to Purchase

A high refractive index of $2.231±0.001$ at 1313 nm is achieved in a colorless, transparent spherical $La4Ti9O24$ glass that was prepared by using an aerodynamic levitation furnace. We also investigate the origin of the high refractive index based on the Lines theory. The physical parameters necessary for the theoretical calculations are the averaged nearest-neighbor Ti–O and La–O distances that are deduced by neutron and synchrotron x-ray diffraction measurement and the partial molar volumes of $TiO2$ and $LaO1.5$ in the glass. The sum of the calculated $TiO2$ and $LaO1.5$ susceptibilities provides a $La4Ti9O24$ glass refractive index of 2.244. This is very close to the experimental refractive index of the glass. In addition, the theoretical calculation results suggest that the oxygen fivefold Ti $(TiO5)$ cluster produces greater susceptibilities than the sixfold Ti $(TiO6)$ cluster in the glass.