Gilbert F. Lee
John D. Lee
Jeffry J. Fedderly
Polymer Sci. Group, Naval Surface Warfare Ctr., 10901 New Hampshire Ave., Silver Spring, MD 20903
At the glass transition of a polymer, the shear sound absorption per wavelength displays a relaxation covering many decades of frequency. Calculations were made of the peak height and half-width of this relaxation based on the Havriliak--Negami dispersion relation. These calculations are an extension of our earlier study of the complex modulus loss factor height and width [B. Hartmann, G. F. Lee, and J. D. Lee, J. Acoust. Soc. Am. 95, 226--233 (1994)]. It was found that height and width are not independent: A high peak has a narrow width while broadband absorption can only be achieved for low-peak heights. The calculation predicts that height times width is approximately constant, as expected for a relaxation for which the area under the curve is constant. These predictions are compared with published experimental data on various polymers, chiefly polyurethanes, and found to be in good agreement.