Upon X-ray irradiation, a number of glasses undergo a fluidization process: The atoms move from their original positions while keeping a similar distribution of interatomic distances, as for two snapshots of a liquid. This process has been studied looking at the atomic displacements over interatomic distances. We here extend these …
Speckle-based experiments, in particular X-ray Photon Correlation Spectroscopy (XPCS), are among the ones that benefit most from the development of next generation light sources. The key quantity that determines whether or not it will be possible to perform an XPCS experiment is the speckle contrast β, which measures the visibility of …
When a liquid is cooled to produce a glass its dynamics, dominated by the structural relaxation, become very slow, and at the glass-transition temperature Tg its characteristic relaxation time is about 100 s. At slightly elevated temperatures (~1.2 Tg) however, a second process known as the Johari-Goldstein relaxation, βJG, decouples from the …
