  The atomistic mechanisms occurring during the processes of aging and
rejuvenation in glassy materials involve very small structural rearrangements
that are extremely difficult to capture experimentally. Here we use in-situ
X-ray diffraction to investigate the structural rearrangements during annealing
from 77 K up to the crystallization temperature in Cu44Zr44Al8Hf2Co2 bulk
metallic glass rejuvenated by high pressure torsion performed at cryogenic
temperatures and at room temperature. Using a measure of the configurational
entropy calculated from the X-ray pair correlation function, the structural
footprint of the deformation-induced rejuvenation in bulk metallic glass is
revealed. With synchrotron radiation, temperature and time resolutions
comparable to calorimetric experiments are possible. This opens hitherto
unavailable experimental possibilities allowing to unambiguously correlate
changes in atomic configuration and structure to calorimetrically observed
signals and can attribute those to changes of the dynamic and vibrational
relaxations ({\alpha}-, {\beta}- and {\gamma}-transition) in glassy materials.
The results suggest that the structural footprint of the {\beta}-transition is
related to entropic relaxation with characteristics of a first-order
transition. Dynamic mechanical analysis data shows that in the range of the
{\beta}-transition, non-reversible structural rearrangements are preferentially
activated. The low-temperature {\gamma}-transition is mostly triggering
reversible deformations and shows a change of slope in the entropic footprint
suggesting second-order characteristics.
