<p>Molecular mechanism driving non-equilibrium polymer glasses toward more thermodynamically stable configurations is commonly attributed to the α-relaxation associated with cooperative segmental motions. However, growing experimental evidence has revealed the presence of a much faster relaxation process that enables partial equilibrium recovery deep in the glassy state. This faster process has also been identified as a universal feature across different classes of glasses. Recent studies have sought to attribute this relaxation to subtle configurational rearrangements of localized ensembles of loosely packed molecular segments embedded in a tightly packed glassy matrix; however, direct experimental visualization of these rearrangements remains extremely challenging. Here, we propose a novel experimental strategy using bimodal atomic force microscopy to observe the temporal evolution of nanoscale mechanical heterogeneities (NMHs) in an epoxy polymer glass under aging below the glass transition temperature (<i>T</i>_g). Our results indicate that even deep in the glassy state, approximately 70 K below <i>T</i>_g, the modulus variations of NMHs persist, albeit in a slow and localized manner, in sharp contrast to the fast and highly cooperative changes observed during aging near <i>T</i>_g. This finding provides real-space evidence suggesting a correlation between the structural rearrangements and a relaxation process much faster than the α relaxation.</p>