Aging of ring polymeric topological glass formers via thermal quench

Abstract

We investigate the dynamical response of glass-forming systems composed of topologically constrained ring polymers subjected to an instantaneous thermal quench, employing large-scale molecular dynamics simulations. We demonstrate that the onset of glassiness depends on polymer stiffness, with increased rigidity enhancing configurational constraints and delaying structural relaxation. In the glassy regime, the system exhibits hallmark aging characteristics, as evidenced by two-time correlation functions, namely the mean square displacement and self-intermediate scattering function, which display a clear dependence on the waiting time following the thermal quench. The extracted relaxation timescale ($τ_α$) follows an approximate simple aging scenario with waiting time ($t_w$), described by $τ_α\sim t_w^b$, where $0.8 < b < 0.93$. Finally, we analyze the threading of rings during the thermal quench, demonstrating that both increased and persistent threading correlate with the emergence of glassiness. Moreover, the threading persistence timescale exhibits a strong correlation with the structural relaxation timescale. Our study thus provides a comprehensive view of structural relaxation and aging in dense ring polymer systems, highlighting the critical roles of topological constraints and polymer stiffness in governing non-equilibrium glassy dynamics.