ULTRASONIC AND VISCOELASTIC RELAXATION IN BIS[M-(M-PHENOXY PHENOXY)PHENYL] ETHER

The velocity of propagation and attenuation of longitudinal waves has been determined for a six ring polyphenyl ether, bis[m (m phenoxy phenoxy) phenyl] ether. The viscosity, density, and shear relaxation properties of this liquid are known from previous measurements. It is found that the relaxing part K2 of the compressional modulus is equal to 43 times the limiting value of the shear modulus Gâ, but the volume viscosity ⋔ r is approximately 4 Ã 43 times the shear viscosity ⋔. Within experimental error, the shape of the reduced relaxation curves for the components of the complex compressional modulus is the same as that found for the corresponding components of the complex shear modulus. This indicates that the shear and compressional relaxation processes have a common origin. These findings are compared with previously published results for associated liquids. © 1969, Acoustical Society of America. All rights reserved.