Characterization and physical properties of PbO-As2O3 glasses containing molybdenum ions

PbO-AS(2)O(3) glasses containing different concentrations of MoO3 ranging from 0 to 1 mol% (in steps of 0.2) were prepared. The samples were characterized by X-ray diffraction, differential thermal analysis and scanning electron microscopy. A number of studies, viz., optical absorption, magnetic susceptibilities, ESR spectra, IR spectra, elastic properties (Young's modulus E, shear modulus G and microhardness H) and dielectric properties (constant epsilon, loss tan delta, a.c. conductivity sigma(ac) over a range of frequency and temperature and breakdown strength), have been carried out on these glasses. Optical absorption, ESR and magnetic susceptibility measurements suggest that when MoO3 concentration is greater than 0.4 mol% in the glass matrix, molybdenum ions exist in Mo5+ state with Mo(V)O3- complexes that act as modifiers in addition to Mo5+ state with MoO4 and MoO6 structural groups. The studies on elastic and dielectric properties indicate that the mechanical and insulating strengths of the glass are considerably high when the content Of MoO3 is about 0.4 mol% in the glass matrix. (C) 2002 Elsevier Science (USA).