Calorimetric signature of secondary relaxation processes in metallic and chalcogenide glasses

A study of the behavior of two different glasses through calorimetric measurements is presented in this work. When undergoing a thermal protocol reaching the glass transition temperature, a glass displays a sudden jump in its heat capacity. This feature signals the kinetic transition from the liquid phase to the disordered, glassy one, where the atomic dynamics becomes incredibly slow. However, some dynamical processes - also called β-relaxation - remain active in the glassy state too. This work is an attempt to emphasize the calorimetric signature of the ꞵ-relaxation in glasses following two different routes, both meant to enhance the heterogeneity of the glass and thus to enhance the β-relaxation strength: the first one is via very-fast quenching (hyperquenching) and the second one is via laser irradiation and the consequent generation of defects in the glass matrix. The first route is performed onto a Pd-based metallic glass, reproducing some results about the β-relaxation in metallic glasses already available in literature. The second path is instead applied to a chalcogenide glass, giving some new, interesting results and opening the way to future developments.