Rebonding: Rebonding uses slightly different chemicals than relaxing as well as heat in order to straighten the hair. Rebonding is done by the application of a solution, usually a perming solution with strong chemicals like sodium hydroxide, guanidine hydroxide, and ammonium thioglycolate or thio. This process breaks the hair bonds. Then a flat iron is used to reset the hair bonds and make the hair straight.
Relaxing: This procedure uses chemicals to straighten the hair by breaking down and reforming the hair’s components. Typically, the treatment does not straighten the hair completely. Rather, it softens very tight or kinky curls. Many women find they still need to straighten their hair after having it relaxed if they want it to be completely straight.