Abstract
Glasses with the chemical formula 39PbO-1NaI- (60-X) Na2B4O7 - X CaO mol % (X = 0, 5, 10, 15, 20, 25 mol %). were prepared by the usual melt quenching technique. The density and the molar volume were determined. Ultrasonic velocities (longitudinal and shear) were measured in these glasses at room temperature. The elastic moduli, such as Young's modulus (Y) or Bulk modulus (K) were determined and elastic properties were calculated in terms of the Makishima-Mackenzie model. The thermal stability criterion Lambda T was determined by using differential thermal analysis (DTA) with heating rate10 degrees C/min.