A STUDY OF MOLECULAR-DYNAMICS AND PHASE-TRANSITIONS IN SOLID MBBA

The solid state polymorphism of liquid crystalline MBBA was investigat ed by temperature dependent NMR spin-lattice relaxation time measureme nts. The sensitivity of the method could be utilized because the corre lation time of the measurement is in the correlation time region of mo lecular motion. Motional correlation time and activation energy values were determined and the results show some interesting changes between the different solid phases. Non-trivial variation in the end-chain ro tational motion in two crystalline phases has been observed. Conclusio ns were drawn on the relationship between rotational molecular dynamic s, intermolecular order and phase transitions.