The isothermal crystallization behavior of thin films of isotactic poly(propylene) between plates coated with chromium, Teflon (R) or gold is studied by polarized light microscopy. At all contact surfaces between poly(propylene) and the other materials, transcrystallinity can be observed and competes with the growth of entities which originate in the bulk phase. The shape of these entities can be described by two intersecting paraboloids.