The mechanisms of molecular mobility and of phase transitions in a thermotropic, comb-shaped, side-chain liquid crystalline polymer (LCP), poly-(epsilon -acryloyloxycaproyloxy-phenyl)-n-butoxybenzoate (PABB) were studied by dielectric techniques (dielectric relaxation spectroscopy, DRS, and thermally stimulated depolarization currents, TSDC). Two subglass secondary relaxations, beta and gamma, were observed in TSDC measurements, at about -100 and -150 degreesC, respectively. The beta relaxation, as well as, the alpha relaxation, associated to the glass transition, were studied by DRS.