Abstract
TiO2 – based and Nb2O5 – based glasses without any network former oxides were prepared by containerless processing. The glasses exhibit excellent optical properties such as high refractive index with low wavelength dispersion, and transparency in visible light. It was indicated that the high refractive index is caused by unusual dense state of highly ionic constituent elements. Structural analyses revealed that the dense packed structure is realized because oxygen coordination numbers of cations are rather larger than those of conventional oxide glasses and the cation-oxygen polyhedra are connected to each other not only by corner-sharing but also edge – or face sharing. These results raise the possibility that novel higher refractive index with lower wavelength dispersion glasses, which contain highly ionic heavy elements at the lower left in the periodic table, may be synthesized.
