Temporal fractal characteristics of activation events during relaxation in disordered materials

The investigation of physical processes across various temporal scales is essential for comprehending and forecasting the behavior of intricate systems over extended periods. Relaxation processes, which span 16 orders of magnitude, are a prime example of multiscale physical processes. However, the description of the relaxation process across multiple time spans is not yet clear. This study employs advanced flash differential scanning calorimetry to probe multiscale relaxation dynamics across various glass systems. We discovered that the relaxation behavior exhibits self-similar scaling across multiple time scales, arising from the accumulation of temporally fractal activation events. Due to the heterogeneous distribution of energy in the system, not every activation event contributes to global energy reduction. Microscopic mechanisms underlying the temporal fractal of activation events are proposed based on both experimental and simulation results. The temporal fractal serves as a critical link connecting microscopic activation events with macroscopic relaxation processes in disordered materials. This fractal framework provides a powerful approach for probing multiscale dynamics in complex systems.