Molecular dynamics simulation is used to reveal the origin of increased molecular mobility that accompanies plastic deformation of a glassy amorphous polymer under an applied stress. Significant increases in torsional transition rates are observed during active deformation prior to and just beyond the yield point. The transition rate drops when active deformation ceases. Increased transition rates are not contingent upon dilation. These simulations verify recent experimental observations of increased mobility during active deformation.

• Received 6 June 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.175505