In the present work, the technique of Thermally Stimulated Depolarisation Currents (TSDC) was used to study the dipolar relaxation mechanisms in two side-chain liquid crystalline polysiloxanes. The studied polymers differ significantly in the structure of the mesogenic side groups and this is at the origin of different features of the corresponding TSDC spectra. It is shown that the TSDC technique is able to separate the motions of the longitudinal (mu(parallel to)) and of the transverse (mu(perpendicular to)) dipole moment components of the mesogenic side groups in the liquid crystalline phase.