What term is used to describe a perm activated by heat created chemically within a product?

The term to describe a perm activated by heat created chemically within a product is exothermic. In the context of permanent waving, an exothermic perm involves a chemical reaction that generates heat as the perm solution processes the hair. This heat can enhance the effectiveness of the curl formation, allowing for stronger and longer-lasting curls.

On the other hand, endothermic perms require an external heat source, such as a hooded dryer, to activate the chemicals in the perm solution. The thermal option is a general term referring to heat in various contexts, while the chemical option broadly encompasses any chemical processes involved in perming. Therefore, exothermic specifically highlights the type of reaction that directly relates to the heat produced within the product, making it the most accurate term for this scenario.