Study on ultrasonic velocity and elastic properties of γ-radiated borate glasses

Longitudinal and shear ultrasonic velocities were measured in different compositions of sodium borate glass samples before and after irradiation with γ-rays. Measurements were carried out at room temperature and at 4 MHz frequency using pulse echo technique. Densities of the glass samples were measured using displacement method while toluene was used as immersion liquid. Elastic constants were calculated as well as Debye temperature, softening temperatures and microhardness for all glass samples. Results showed that the effect of radiating sodium borate glass with γ-radiation had no noticeable change on ultrasonic velocity. However, the effect of increasing sodium oxide content on ultrasonic velocity was very clear. The increase in velocity was attributed to the gradual increase in the rigidity of the glass and hence strengthening of the network due to the gradual change of boron atoms from the three-fold to the four-fold coordination of oxygen atoms.