We present the results of molecular dynamics simulations of PEO(x)Nal polym
er electrolytes, performed to study the influence of NaI on the dynamics of
PEG. By calculating the mean square displacement of the CH2 groups we obse
rve that the Rouse-like motion, typical for short polymer chains, is slowed
down under the influence of NaI. This slowing down is also observed in the
self part of the intermediate scattering function F-s(k, t), as an increas
e in the relaxation time. By using the Gaussian approximation it is shown t
hat the stretched exponential relaxation in the small k-limit of F-s(k, t)
is a result of the Rouse-like motion of the polymers. We find that our resu
lts are in good agreement with neutron spin-echo experiments. (C) 2000 Else
vier Science B.V. All rights reserved.