Rapid thermal annealing enables removal of orientation defects in planar cholesteric liquid crystal (CLC). We investigate influence of rapid annealing and cooling on molecular orientation in CLC. Annealing temperature strongly affects the number of treatment cycles required for improved orientation, and an effective annealing temperature range is very narrow. Both annealing and cooling are effective for removal of orientation defect in planar CLC. The number of the treatment cycles depends on viscosity of CLC. The rapid thermal processing is applicable to chiral dopants having various thermal properties.