  Orientational dynamics in the isotropic phase of a comb-shaped nematic
polymer with mesogenic and functional side groups was studied using the Kerr
effect and dielectric spectroscopy. For the first time, it was found that in a
mesogenic polymer, in contrast to low-molecular-weight mesogens, the relaxation
of the electric birefringence of a melt above the temperature of the
nematic-isotropic phase transition can be presented by a sum of several
exponential processes, two of which play a decisive role. These main processes
replace each other in a temperature range of about fifty degrees. Dielectric
spectroscopy also made it possible to distinguish two processes of
orientational relaxation: the first is due to rotation of the side mesogenic
groups, and the second is associated with motion of the main chain segments.
