It was established experimentally that the value of the thermal expansion coefficient of metallic glasses subjected to preliminary isothermal annealing over a range of temperatures, characteristic for the process of structural relaxation, is determined by the velocity of subsequent heating. The thermal expansion coefficient value of preliminary annealed metallic glasses, heated at a relatively high rate of 0.2 °C s −1, may exceed the thermal expansion coefficient of initial as-quenched samples several fold. Contrary to the existing notion about the irreversibility of the volume decrease during structural relaxation of metallic glasses provoked by annealing, it was discovered that sufficiently rapid heating of preliminary annealed samples may lead to an increase in metallic glass volume up to a value close to the volume of the initial alloy in the temperature range analysed. The result confirms the proposition of the model of “frozen-in” crystallization centres regarding the possibility of partial reversible solution of a crystalline phase in an amorphous phase within the restricted temperature range in which metallic glasses exist.