Using ultrasonic phase comparison and phase detection method, the longitudinal and shear sound velocities and their temperature dependences of a breakaway glass have been measured up to 73℃. The elastic moduli, such as bulk modulus, Young's modulus and Poisson's ratio have been determined. The results indicate that this breakaway glass exhibits a turning point in the velocites and elastic moduli vs, temperature curves at about 54℃. The measured values are in good agreement with Brillouin scattering data at ...