We study the transitions between morphological phases of an oligofluorene ( pentamer) thin-film using temperature-dependent photoluminescence emission. We find that the so-called beta-phase can be created by cooling an amorphous thin-film to 80 K and then slowly returning it to room-temperature. This process is however suppressed if the thin-film is initially prepared in a poly-crystalline form. We also demonstrate that the presence of molecules in the beta-phase suppresses the room-temperature crystallization that otherwise occurs in an amorphous film. (C) 2008 Elsevier B. V. All rights reserved.