Electronic polarizability, optical basicity and non-linear optical properties of oxide glasses

The average electronic polarizability of the oxide ion alpha(O2-)(n(o)) of numerous binary oxide glasses (phosphate, berate, silicate, germanate, tellurite and titanate) has been estimated on the basis of the refractive index reported in literature. An optical basicity scale has been proposed on the basis of a good agreement between calculated theoretical optical basicity Lambda(th) and refractive index based optical basicity Lambda(n(o)) of the glasses. It was established that third-order non-linear optical susceptibility chi((3)) of the glasses, also found in the literature, increases with increasing optical basicity and tendency for metallization of the glasses. This is associated with the high electron donor ability of the oxide ions and the small optical band gap. Conventional oxide glasses with low refractive index possess low polarizability, low optical basicity, large metallization criterion and small chi((3)). Tellurite and titanate glasses as well as berate glasses containing a large amount of Sb2O3 and Bi2O3 with high refractive index above 2.0 show large polarizability, high optical basicity, small metallization criterion and large chi((3)). (C) 1999 Elsevier Science B.V. All rights reserved.