ULTRASONIC MEASUREMENTS ON A FRAGILE GLASS-FORMING LIQUID CLOSE TO THE GLASS-TRANSITION

The behavior of acoustic attenuation and sound velocity in a fragile l iquid (m-fluoroaniline) across its calorimetric glass transition, T-g, is presented. This liquid offers the opportunity to observe its dynam ical response continuously over an extended temperature domain inside which crystallization does not occur. The experiments were performed a t ultrasonic frequencies (5-30 MHz) in the temperature range 150-300 K . The main frequency-dependent process is clearly due to the alpha or structural relaxation.