Quasielastic neutron scattering (QENS) studies on the reorientational dynamics in the ordered phases (crystalline and the smectic H) of p-n-hexyloxybenzylidine-p'-n-butylaniline (6O.4) are reported here. Analysis of the QENS data showed that in the crystalline phase (room temperature similar to 25 degrees C) the reorientational motion involves only the core of the molecule, whereas in the S-H phase (at 45 degrees C) the whole molecule is involved. This motion is found to persist even when the sample was cooled back to 25 degrees C (below the crystalline SH transition temperature of 33.7 degrees C) suggesting existence of the liquid crystalline phase as a supercooled state. DSC measurements and X-ray diffraction studies corroborate the QENS results. (C) 2008 Published by Elsevier B.V.