Acoustic behaviour of zinc chloride p osphate glasses

The effect of hydrostatic pressure and temperature on the velocities of longitudinal and shear ultrasonic waves propagated in (ZnCl/sub 2/)/sub x/ (P/sub 2/O/sub 5/)/sub 1-x/ glasses (x = 0.2, 0.3, 0.5) have been measured. The hydrostatic pressure derivatives (del C/sub 11/del p) and (del C/sub 44/del P) of the longitudinal (C-s 11 and shear C-s 44 elastic stiffness are negative: both longitudinal and shear acoustic mode Grueneisen parameters are small and negative: the application of hydrostatic pressure results in softening of the long wavelength acoustic mode phonon modes. (authors)