Dynamics of a low temperature phase transition in liquid crystal TB10A probed by Raman spectroscopy

Raman spectra of TB10A were recorded in the regions, 925-1000 and 1140-1220 cm(-1) from room temperature down to 20 K, during cooling and healing cycl es. The subtle changes in the spectral features of the bands at similar to 975 and similar to 1195 cm(-1) at 47 K were attributed to a hitherto unrepo rted stable-metastable phase transition in TB10A. The dynamics of the new p hase transition have been explained in terms of splitting of the non-planar mode at similar to 975 cm(-1) owing to strong intermolecular interaction d ue to close molecular packing in the low temperature phase. The spectral an omaly of the 975 cm(-1) band, in terms of variation of relative intensity w ith respect to temperature, also shows the hysterisis linked with the proce ss of stable-metastable-stable modification in TB10A.