Relationship between the heat flow and relaxation of the shear modulus in bulk PdCuP metallic glass

We measured the heat flow, shear modulus and density changes occurring upon heating of bulk glassy Pd41.25Cu41.25P17.5, which polymorphically crystallizes into tetragonal Pd2Cu2P with simultaneous decrease of the density. It was found that the heat release (well below the glass transition temperature Tg) and heat absorption (near and above Tg) are uniquely linked to the relaxation of the shear modulus through the relaxation change of the concentration of internal “defects” frozen-in upon glass production. The two models suitable for a quantitative description of this interrelationship are discussed in detail. The obtained results clearly demonstrate an intrinsic connection of the shear moduli of glass and maternal crystal.