SUB-TG-ALPHA' RELAXATION IN A PDCUSI GLASS - INTERNAL-FRICTION MEASUREMENTS

Internal friction measurements on a Pd//7//7//. //5Cu//6Si//1//6//. //5 glass reveal two distinct relaxation processes; the sub-T//g alpha prime relaxation and the near T//g alpha relaxation. The alpha prime relaxation is anelastic in origin and arises from the frozen-in relaxation sites of the two-level system. The internal friction spectra have a broad distribution of the form, Q** minus **1 approximately equals Q//0e** minus ** alpha e**b**T. A model based on free-volume fluctuation is proposed.