Hypersonic relaxation in amorphous polymers

In order to more fully understand the viscoelastic properties of amorphous polymers, it is desireable to have dynamic mechanical data over as wide a range in frequency as possible. One useful technique for studying the high-frequency behavior of polymers is to measure the velocity and attenuation of sound waves in the polymer fluid. When the frequency exceeds 109Hz. the sound waves are called hypersonic acoustic phonons. The present review examines the dynamic data obtained in the GHz frequency range for amorphous polymers.