Relaxation Spectrum of Glass

RELAXATION spectra for different kinds of glass, all containing sodium and potassium as common constituents, have been obtained from lateral vibrations over a frequency-range from 5 to 1,500 c./s. It has been found that, in addition to relaxation by thermo-elastic currents, the internal friction at room temperature (26° C.) shows two other common peaks independent of the diameter, one at 50 c./s. and the other at 500 c./s. Evidence for the peak at 50 c./s. has already been given by one of us 1 .