Structural relaxations in glass forming poly(butadiene): A molecular dynamics study

We present results of a molecular dynamics simulation of a realistic model of poly(butadiene). We find Rouse-like dynamics and the corresponding diffusion coefficient shows a power law behavior. The coherent intermediate scattering functions clearly show a crossover from Debye to non-Debye relaxation. The latter can be described accurately by a stretched exponent. It is shown that the second scaling law of the mode-coupling theory is valid for k=1.60 and 2.40Å^-1 in the temperature range measured. The corresponding relaxation times also follow the temperature dependence of the mode-coupling theory.