The 24-µs simulation served as a source of independent, entangled PE melt configurations for this study. Due to the slow dynamics of entangled polymer melts, there had to be substantial time gaps between the selected configurations to ensure that they were independent. According to reptation theory, a polymer chain is confined to a tube-like region arising from surrounding constraints, such as other polymer chains in the case of an entangled polymer melt, and the polymer chain's disengagement time represents the characteristic relaxation time associated with the chain adopting a new tube via diffusion. This disengagement time is thus associated with the timescales on which a chain "forgets" its previous local environments and conformation. As de Gennes demonstrated, the polymer chain end-to-end vector correlation function (< P(t) • P(0) > where P(t) is the end-to-end vector of a chain at time t) decays exponentially according to the disengagement time. Therefore, < P(t) • P(0) > was calculated for the polymer chains in the 24-µs NVT simulation. Fitting the resulting curve to an exponential decay (R 2 > 0.99) yielded a disengagement time of ∼78 million time steps (∼1.6 µs).