Spectroscopic and dielectric studies on PbO–MoO₃–B₂O₃ glasses incorporating small concentrations of TiO₂

Abstract

This paper deals with the investigation of a variety of physical properties including dielectric constant (over a wide range of frequency and temperature), optical absorption, luminescence, electron spin resonance (ESR) and infrared spectra of a TiO₂-doped lead molybdenum borate glass system. The composition chosen for the study is 30PbO–4MoO₃–(66–x)B₂O₃:xTiO₂ (with x ranging from 0.2 to 2.0). Quantitative analysis of the results of this study shows that, when the content of TiO₂ is around 0.8 mol%, the titanium ions exist predominantly in the tetravalent state and occupy substitutional positions in the glass network. A substantial increase in the insulating strength of these glasses on TiO₂ doping has also been observed. When the concentration of TiO₂ is increased beyond 0.8 mol%, it is observed that titanium ions exist primarily in the Ti³⁺ state and molybdenum ions in the Mo⁵⁺ state; analysis of the results further suggests that both of these ions participate in the depolymerization of the glass network.