Fig. 3: KWW and KWW_MULTI fit results.

Reference differential scanning calorimetry (DSC) scans for heating and cooling are provided in (A, D). The temperature range is accordingly separated into three regions, glass (dark gray background), glass transition (light gray background), and SCL (white background). B, C, E, F compare the relaxation time and shape exponent data resulting from conventional Kohlrausch-Williams-Watts (KWW) and KWW_MULTI fitting of the g₂ data sets (each set consists of 96 mean values). The error bars represent the standard errors of the fits. As demonstrated in Fig. 1, KWW only provides meaningful results in the SCL state, while KWW_MULTI excels in the glass and glass transition region but appears redundant in the SCL. Accordingly, the data sets are reported only for the temperature regions where the different models provide reliable and more accurate fits (see also Supplementary Fig. 2 in the SI). The KWW fit parameters in the SCL show typical liquid behavior, namely a steep temperature dependence of τ and β values below 1. In the glass transition region, the KWW_MULTI approach reveals large differences between its two components KWW_C and KWW_S: While the KWW_C parameters follow glass-typical trends, in particular a relatively temperature-insensitive course of τ_C and a highly compressed shape, the KWW_S parameters show liquid-like behavior in form of a steep temperature dependence of τ_S and a stretched shape.