Heavy metal based oxide glasses with composition (100-y) [30 B2O3 .70 Bi2O3] y Fe2O3 (y=0,2,5,7,10) were prepared by the standard melt quenching technique. The amorphous nature of the samples was ascertained using Xray diffraction patterns. The microstructure of the glasses is identified by scanning electron microscopy (SEM) studies. The glass density (d) and molar volume (Vm) both decrease with increase in Fe2O3 content. The change in both the density and molar volume were discussed in terms of the structural modifications that take place in the glass matrix upon increasing Fe2O3 content. The theoretical optical basicity of the prepared glasses is also estimated. The structural changes in these glasses have been investigated by IR spectroscopy. The values of characteristic glass transition temperature (Tg) crystallization temperature (Tc) and melting temperature (Tm) have been found from Differential Scanning Calorimetry (DSC) traces. The glass transition temperature (Tg) increase as the content of Fe2O3 increases.
