BaO-Fe2O3-P2O5 glasses: Understanding the thermal stability

Abstract

The effect of barium oxide on the structure of iron phosphate glass was investigated by Raman spectroscopy to understand the better thermal stability of barium loaded iron phosphate glasses compared to iron phosphate glass containing caesium oxide. Glasses with composition (mol %) of 36.1 Fe2O3-54.1 P2O5- 9.8BaO and 32.2 Fe2O3-48.3 P2O5- 19.5BaO revealed the existence of higher concentration of meta phosphate linkage, which could be a reason for their enhanced thermal stability. In addition, the enthalpy increment data were obtained by isoperibol drop calorimetry on these glasses. These data of barium oxide loaded iron phosphate glasses were compared with those of caesium loaded iron phosphate glasses. The specific heat of pristine IPG is always higher than that of IPG containing either BaO or Cs2O, showing the effect of modifiers (Ba2+ or Cs+) in glass. Depending on the concentration of the modifier, the density of the glass changes and higher the density lower was the specific heat of the glass.