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Cooling rate dependence of the glass transition temperature of polymer melts : a Molecular Dynamics study
A coarse-grained bead spring model of short polymer chains is studied by constant pressure
molecular dynamics ~MD! simulations. Due to two competing length scales for the length of
effective bonds and the energetically preferred distance between nonbonded beads, one observes a
glass transition when dense melts are cooled down ~as shown in previous work, at a pressure p
51 the mode coupling critical temperature is at Tc'0.45 and the Vogel–Fulcher temperature is
T0'0.33, in Lennard-Jones units!. The present work extends these studies, estimating a
cooling-rate-dependent glass transition temperature Tg(G) by cooling the model system from T
50.6 down to T50.3, applying cooling rates from G'1023 to G'1026 ~in MD time units!, and
attempting to identify Tg(G) from a kink in the volume versus temperature or potential energy
versus temperature curves. It is found that Tg(G) lies in the range 0.43