How do organic peroxides form free radicals when warmed in solution?

Organic peroxides form free radicals when warmed in solution because they possess exceptionally weak chemical bonds. These bonds are susceptible to thermal energy, which causes the molecules to undergo irreversible decomposition.1

When these peroxides are heated, the weak bond—specifically the covalent bond linking the two oxygen atoms—breaks, resulting in the formation of free radicals. For example, diacetyl peroxide decomposes upon warming into carbon dioxide and methyl radicals. Once formed, these highly reactive, transient species often proceed to attack surrounding organic solvents, frequently by abstracting hydrogen atoms to form new products. Because of this ability to generate reactive intermediates, organic peroxides are widely utilized as initiators in polymerization reactions.21