A study was conducted to demonstrate the high-temperature annealing of spherical block copolymer micelles in an ionic liquid. The formation of nonergodic micelles of polybutadiene-poly(ethylene oxide) diblock co-polymers and its relaxation in an ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfony)imide were investigated during the study. The wide liquid temperature ranges characteristic of ionic liquids accelerated the formation of block copolymer dispersions, which further allowed to relax at high annealing temperatures. It was observed that the steady-state structures remained highly path dependent despite the thermal energy produced to the system. The two narrow distributions of spherical micelles were also obtained that were dependent on the preparation procedure. The understanding of micelle formation and relaxation process can be used to examine the equilibrium state of steady-state morphologies.