STRUCTURAL STUDIES, ELASTIC AND PHOTOELASTIC PROPERTIES OF LEAD PHOSPHATE, BARIUM PHOSPHATE AND LEAD BARIUM PHOSPHATE GLASSES
The investigation of the atomic structure of glass and its corresponding crystals not only allows us to interpret its elastic and photoelastic properties, but it also allows us to predict the properties of glass which have not been produced yet or are toxic to synthesize. In order to find a correlation between elastic and photoelastic properties with the composition and atomic structure, a series of ternary (PbO)x(BaO)50-x(P2O5)50 (x=10 to 50 mol%) as well as binary (PbO)x(P2O5)100-x (x=50 to 60 mol%) and (BaO)x(P2O5)100-x (x=50 to 55 mol%) compositions have been synthesized via traditional melt quenching techniques and their compositions were verified through wavelength-dispersive spectroscopy (WDS). The local environment of lead and phosphorus as well as the glass atomic structure were investigated with 31P and 207Pb solid-state nuclear magnetic resonance (ssNMR) spectroscopy and derived molar volume from density measurements. The longitudinal and transverse wave velocities (vL and vT ) were determined using Ultrasonic Echography Method (USE). The experimental density values along with the vL and vT were then used to calculate the elastic properties in each series of glass compositions: the longitudinal, bulk, shear, and Young's moduli as well as Poisson ratio. Refractive indices, the sign and value of stress optic coefficient (C) were measured via Abbe refractometer, PS-100 Polariscope and the Senarmont compensator method, respectively. The reliability of the empirical model of photoelasticity was tested and discussed.