anneal (en)

(verb) to heat and then cool (as steel or glass) usually for softening and making less brittle / (verb) to cool slowly usually in a furnace / (verb) to heat and then cool (double-stranded nucleic acid) in order to separate strands and induce combination at lower temperature with complementary strands / (verb) strengthen toughen / (verb) to be capable of combining with complementary nucleic acid by a process of heating and cooling