Glass Forming Region and Ti⁴⁺ Co-Ordination Number in R₂O-TiO₂ (R=Rb, K, Na) and BaO-TiO₂ Binary Glasses

Abstract

R₂O-TiO₂ (R=Rb, K, Na) and BaO-TiO₂ binary glasses have been prepared by the splat quenching method to determine the glass formation region. The oxygen co-ordination number of Ti⁴⁺ was estimated by both infra-red (IR) and photoacoustic spectroscopies (PAS). Glass formation region identified by electron diffraction extended with increasing estimated cooling rate. PAS spectra of these glasses may be more sensitive to the co-ordination number of Ti⁴⁺ than IR spectra. The ratio of oxygen 4-fold coordinated Titanium ion (Ti⁴⁺(4)) oxygen 6-fold coordinated Titanium ion (Ti⁴⁺(6)) could be determined from the computer analysis of PAS spectra. Ti⁴⁺(4) and Ti⁴⁺(6) were co-existent in binary titanate glasses, and the ratio Ti⁴⁺(4)/Ti⁴⁺(6) may be determined by the basicity of glasses, that is, the fraction of Ti⁴⁺(4) were increased with increasing the basicity of glasses. It was concluded that the fraction of Ti⁴⁺(4) in these glasses depended on the basicity parameter using the ionic potential of cation in basic oxides.