Heat treating works primarily with white woods to increase the compression strength. I have also used it on osage with good results.
To heat treat a bow I clamp it to a form with some reflex added and heat the belly with a heat gun until it is chocolate brown. Then I leave it in the form for 3 or 4 days so the wood will rehydrate after the heating. Do not heat treat the back of your bow and be careful you don't accidently do that while heating the belly.