The physical properties of the ionic conductor, obtained by dissolution of lithium trifluoromethanesulphonylimide in polyethylene oxide, (PEO)nLi+((CF3SO2)2N)- have been investigated for several values of n. The phase diagram has been established from both DSC and NMR techniques. The diffusion coefficients of 7Li and 19F containing Species, determined by the pulsed magnetic field gradient (PMFG) technique, are interpreted as the measures of the cationic and anionic transport numbers, which are concentration dependent, and t+ reaches a value close to 0.3. This study is complemented by a systematic analysis of the behaviour of the 7Li relaxation time T1 versus temperature and concentration which is correlated to the glass temperature Tg.

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The physical properties of the ionic conductor [Formula: see text], obtained by dissolution of lithium trifluoromethanesulphonylimide in poly(propylene oxide), have been investigated for several values of n. The glass transition temperature [Formula: see text] has been established from both DSC and NMR techniques. The diffusion coefficients of [Formula: see text]-containing species have been determined by the pulsed magnetic field gradient technique. The behaviour of the proton relaxation time [Formula: see text] versus temperature and concentration has been correlated to the glass temperature. The behaviour of the proton transverse relaxation function, obtained by the spin-echo technique, has been interpreted using a simple model in which two regimes and consequently two transverse relaxation times coexist and are assigned to the `entangled' and `non-entangled' parts of the high-molecular-weight polymer chains investigated.

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We investigate the NMR relaxation of solvent nuclei in non viscous paramagnetic solutions, in the case where the electronic spin of the paramagnetic species is submitted to an internal hyperfine field H hyp . General expressions of the intermolecular longitudinal relaxation rates 1/T 1 are provided, and three distinct regimes corresponding to an applied external field lower, larger and much larger than H hyp appear, with three distinct linear laws for the relaxation rate 1/T 1 vs ν I 1/2 , where ν I is the nuclear resonance frequency. From each of these laws and mainly the third one, it is possible to derive the relative diffusion constant of the paramagnetic and solvent molecules without any model assumption for solutions with a rather high radical concentration of 10 -1 mol L -1 . This is illustrated for a triglyme solution with new stable 15 NTMIOD free radicals at various concentrations. For this solution, T 1 measurements were performed at ν I ) 244 MHz, then at low and intermediate frequencies by the field cycling technique and finally in the Earth's magnetic field. From these results and from measurements of the solvent molecule diffusion constant by the pulsed magnetic field gradient technique, a determination of the diffusion constant of the free radicals is obtained which is compared with that obtained from a direct ESR measurement at low concentration. These data are used for the interpretation of the frequency and temperature dependence of the relaxation rates in this solution.