Mechanical cycling and DSC tests

1.We designed a series of loading waveforms ranging from rectangular and trapezoidal waves to triangular waves, with a particular focus on the effects of asymmetric loading-unloading ratios in triangular waves. All waveforms were applied in tension mode using a commercial dynamic mechanical analyzer (DMA, TA instrument Q800). The experiments were tested at 417 K with a fixed stress amplitude of 200 MPa (below the yield strength to ensure a dominant linear response). The period tcycle was uniformly set to 120 s for consistent comparison. Rectangular waves, representing the extreme case with the longest hold time, were used to explore structural evolution under constant stress. The waveform characteristics are composed of hold time as 99.99% of the period (γhold→1, where γhold is the hold time fraction, i.e., the ratio of hold time to tcycle) and rise (instantaneous loading to peak stress) and fall (instantaneous loading to zero stress) time approaching 0; Trapezoidal waves, serving as a transition between rectangular and triangular waves, introduced a controllable hold time to study the synergistic effects of the three stages: “rise-hold-fall”. Their parameterization is defined as: Rise γrise and fall time γfall were fixed at γrise =γfall = (1-γhold)/2). By varying the hold time (γhold =0.01, 0.16, 0.33, 0.5, 0.67, and 0.83), the critical impact of hold duration on net energy accumulation was quantified; Triangular waves, with no hold phase (γhold =0), were used to purely investigate the influence of stress rate distribution on rejuvenation. The waveform is characterized by “linear rise + linear fall”, with the core parameter being rise ratio γrise =0.01, 0.2, 0.4, 0.6, 0.8, and 0.99, corresponding to significant differences in loading and unloading stress rates.2.Thermal properties of glassy samples were characterized by differential scanning calorimetry (DSC, Netzsch 214). Samples were heated from 323 K to 673 K to induce complete crystallization, cooled to 323 K, and then reheated to 673 K for baseline acquisition. Relaxation enthalpy (also named configuration energy Uc) was computed by integrating exothermic heat flow curves. Aged samples were tested at a heating rate of 3 K/min. For the cycled samples, the acceleration section was removed and a heating rate of 10 K/min was used.3.The meanings of the row labels and column labels in the table data sheet have been clearly indicated in the document.