Dynamical perspective of stability in glasses

Glasses are intrinsically out-of-equilibrium materials, and their stability plays a central role in determining both their physical properties and their technological performance. This Thesis investigates how glass stability influences microscopic dynamics over a wide range of timescales, from picosecond vibrations to structural relaxations lasting hundreds of seconds. Different stability regimes are explored by combining distinct preparation methods, such as physical vapor deposition, with thermo-mechanical treatments including X-ray irradiation and high-pressure compression. Vibrational dynamics are characterized through the vibrational density of states measured by Nuclear Resonant Analysis of Inelastic X-ray Scattering and Raman spectroscopy, while slow relaxation processes are probed via X-ray Photon Correlation Spectroscopy. Fast nanocalorimetry provides complementary information on the macroscopic stability of compressed samples. The results show that ultra-stable glasses exhibit vibrational signatures consistent with enhanced thermodynamic stability. X-ray irradiation induces localised yielding leading to rejuvenation, whereas high-pressure experiments reveal rejuvenation upon compression, a polyamorphic transition, and an unexpected non-monotonic pressure dependence of the dynamics. Altogether, these findings establish a clear link between stability, preparation history, and dynamical behaviour, offering a comprehensive perspective on how external treatments and fabrication routes govern the energy landscape of amorphous solids.