Molecular Motions and Polymorphic Phase Transitions in (CH3)4NClO4, and (CH3), NHCl04 as Studied by NMR

The temperature dependences of the proton spin-lattice relaxation times T1, T1p, and T1D as well as the second moment M2, are reported for the phase II of tetramethylammonium perchlorate (CH3)4, NClO4, and for the phases III, II, and I of trimethylammonium perchlorate (CH3), NHCl04. An analysis of these data allows to reveal various molecular motions in the appropriate phase modifications and to determine their activation energies and correlation times.