Unveiling the elastic properties of PbF2-MoO3-Bi2O3-B2O3 glass: A comprehensive analysis using FTIR and Raman spectroscopy

This work investigates the structural and elastic properties of x PbF2 - 20 Bi2O3 - 10 MoO3 - (70-x) B2O3 (where x = 0, 5, 10, 15, and 20 mol%) glasses with an emphasis on the effects of different PbF2 concentrations. Amorphousness of the samples is confirmed by X-ray diffraction (XRD) inspection because no identifiable peaks are present. Changes in the connectivity and structure of the glass network can be detected by the observed 17 % increase in glass density from 4.1024 g/cm3 to 4.7956 g/cm3 as PbF2 concentration increases. FTIR and Raman spectroscopy investigations revealed the increase of PbF2 results in the creation of Pb 2+1/2 [F-BO4/2], [PbF9+] units and the conversion of BO3 to BO4 units. These structural changes are emphasised by the shift towards higher wavenumbers and the progressive widening of the bands from 1200 cm-1 to 1500 cm-1. The results show an increase in the proportion of N4 with additional PbF2, which affects the elastic properties of the glass. The computed elastic moduli demonstrate that the increase in [PbF9+] structural units caused by PbF2 addition causes polymerization in the molybdenum bismuth-borate network. The increasing rigidity of the glass network is further increased by the formation of highly coordinated [PbF9+] and by the increasing parameters of KMM and KBC.