2007 Volume 48 Issue 7 Pages 1708-1710
The isothermal relaxation processes of bulk Zr50Cu40Al10 and Pd42.5Cu30Ni7.5P20 glasses were examined by density reduction associated with relaxation. Density experiments were carried out by buoyancy method at room temperature. The isothermal relaxation curves were best fitted by a stretched exponential function with a Kohlrausch exponent less than unity. Based on free volume model, the reduced free volume xfas=0.0355 and flow defect concentration Cfas=5.80×10−13 in as-quenched state was obtained for Pd42.5Cu30Ni7.5P20 glass. However, the temperature at which the free volume started to deviate from equilibrium concentration on cooling of the melt was not in accordance with calorimetric glass transition temperature.