but i think it definitely would if it were boiled (ie the freebase) with NaOH present as the OH can cleave and become a highly reactive chemical (sodium), i'm not talking 100 or 200 degrees here though, i mean like in a basepipe, 250-400 (to be properly correct, superheated). What would sodium do to these alkaloids? I don't think it would be pretty.
in those conditions you mentioned, the dmt would boil out very very rapidly. the dmt would be all over the reflux condenser, if not lost to the atmosphere.