The structural relaxation behavior in the Pd40Cu30Ni10P20 and the Pd43Cu27Ni10P20 metallic glasses was examined by the differential scanning calorimetry and the electrical resistivity experiment. A sharp endothermic peak in the DSC thermogram appeared just before the supercooled liquid region for the sample annealed at 540K during a given time ranged from 864 to 2940ks. Although the peak area, ΔHg, increased with annealing time, it did not saturate within the experiment. The room temperature Mossbauer experiment was performed to examine the change in the amorphous structure of the Pd40Cu30Ni9 57Fe1P20 glass accompanied with the structural relaxation at 540K. A Mössbauer spectrum showed an asymmetrical doublet peculiar to the paramagnetic metallic glass. The average isomer shift and quadrupole splitting decreased with time up to 1440 ks and thereafter increased. The behavior of these parameters was interpreted within the framework of the free volume theory.
