Bruce Hartmann
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.