We investigate the dynamics of aF=1 spinor Bose-Einstein condensate of87Rb atoms confined in aquasi-one-dimensional trap both at zero and at finite temperature. At zero temperature, we observe coherentoscillations between populations of the various spin components and the formation of multiple domains in thecondensate. We study also finite temperature effects in the spin dynamics taking into account the phasefluctuations in the Bogoliubov-de Gennes framework. At finiteT, despite complex multidomain formation inthe condensate, population equipartition occurs. The length scale of these spin domains seems to be determinedintrinsically by nonlinear interactions.