The structural investigations of PbO–P2O5–Sb2O3 glasses with MoO3 as additive by means of dielectric, spectroscopic and magnetic studies

40PbO–40P2O5−(16+x)Sb2O3:(4−x)MoO3 glasses with nine values of x ranging from 4 to 0 were prepared. A number of studies viz., differential thermal analysis, infrared, optical absorption, Raman and ESR spectra, magnetic susceptibility and dielectric properties (constant ε′, loss tan δ, AC conductivity σAC over a range of frequency and temperature) of these glasses have been carried out. The results have been analyzed in the light of different oxidation states of molybdenum ions. The analysis indicates that when the concentration of Sb2O3 is less than 19.0 mol% in the glass composition, molybdenum ions are observed to exist mostly in Mo5+ state, occupy network-modifying positions and decrease the rigidity of the glass network.