The surface of azobenzene polymer films could be photo-fabricated into various surface relief structures. Most of surface grating formation studies were focused on polymeric materials because of the easy film formation. In this work, we investigated the photo-manipulation of low molecular weight tri-isocyanate cyclic compounds containing azobenzenes which form glassy films upon spin casting. Theses nonpolymeric films were capable of forming efficient surface gratings when irradiated to an interference pattern of polarized laser beams. We examined the difference of the grating formation behaviors between the isocyanate trimer and polyisocyanate films containing azobenzene groups with the same chemical compositions. The surface grating formation on the trimer film was more efficient than on the polymer films even though both films have similar T(g)s.