Ultrasonic Study of Hydrated Fused Salts.
Final rept. 1 Oct 66-1 Oct 70,
POLYTECHNIC INST OF BROOKLYN N Y DEPT OF CHEMISTRY
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The object of the research reported was the study of the ultrasonic relaxation of hydrated fused salts in order to investigate their dynamic behavior when subjected to a high frequency ultrasonic wave. In particular it was of interest to study the relaxation of molecular translation of processes like the formation of molecular complexes. The possibility of the occurrence of viscoelastic relaxation processes for ionic solutions, a study so far never performed, was also considered. This last type of research was important because of the paeudo-glass transition that could have been observed for these liquids if a viscoelastic relaxation occurred. CaNO32.4H2O was first investigated from room temperature to 75C. A relaxation of the sound absorption at 20MHz was noticed. This relaxation was classified as thermal namely due to the relaxation of some molecular complex after the passage of the sound wave. The barrier of energy of the process involving this molecular complex was found to be larger than the one forviscous flows. A later study established that after the relaxation the residual volume viscosity showed the same barrier of energy as the viscous flow. In particular the non-Arrhenius behavior of the shear viscosity was also shown by the volume viscosity. Author
- Physical Chemistry