7Li and 19F NMR relaxation time (T1, T2, T1 rho) measurements have been used to probe the dynamics of LiCF3SO3 dissolved in an amorphous co-polymer poly(ethylene oxide-co-propylene oxide), and in particular the influence of the plasticising agents propylene carbonate and dimethyl formamide. The changes in relaxation behaviour of 19F and 7Li with increasing plasticiser concentration are very different, as is the effect of each plasticiser. These differences can be explained qualitatively in terms of the interaction between the plasticiser and the ions. Preliminary 7Li T1 rho measurements reveal two components at low temperatures.