Electric field effects on absorption and emission spectra and emission decay have been examined for tris(8-hydroxyquinoline) aluminum (Alq(3)) doped in a poly(methyl methacrylate) film. Emission spectra as well as absorption spectra of Alq(3) exhibit the so-called Stark shift in the presence of external electric field, and a significant change in electric dipole moment takes place following the optical transition. Fluorescence of Alq(3) also shows the electric-field-induced quenching, which is confirmed to originate from the field-induced increase in intramolecular non-radiative decay at the emitting state by the direct measurements of the field-induced change in fluorescence decay profile. (C) 2008 Elsevier B.V. All rights reserved.