Ultrasonic Study Of (Agi)X(Ag4p2o7)1-X Glasses In The Region Of The Glass-Transition Temperature

Ultrasonic velocity and attenuation have been measured on the superionic-glass system (AgI)x(Ag4P2O7)1-x, With 0.50 less-than-or-equal-to x less-than-or-equal-to 0.875, from room temperature to 200-degrees-C through the glass-transition temperatures. X-ray diffraction, differential scanning calorimetry, and density measurements were made, besides ultrasonics, to clarify the nature of the supercooled liquid, with or without dispersed crystallites. We observed velocity dispersion and a single attenuation peak for 0.5 less-than-or-equal-to x less-than-or-equal-to 0.75 glasses, which decreased in location with increasing x in close correlation with the glass-transition temperature, and was assigned as due to relaxation of the supercooled liquid. For more AgI content, 0.80 less-than-or-equal-to x less-than-or-equal-to 0.875, another attenuation peak(s) and velocity peak(s) were detected and were considered to be due to nucleation and/or crystallization of some unidentified crystal(s).