X-ray absorption fine structure has been used to elucidate the local environment of ions in polymer electrolytes formed from short-chain oligomers of polyethylene oxide. The gel sectioning technique has been used to measure the radiotracer diffusion coefficients of Na+ and H2O in oligomeric polymer electrolytes. The diffusion coefficient has been studied with respect to a wide concentration and temperature range. Activation energies for diffusion were obtained for Na+ and H2O. Activation energies for diffusion and diffusion coefficients have been obtained for the oligomer chains by means of pfg-NMR.