The photo luminescence (PL) fatigue after illumination of pulsed laser light has been studied for a-Si:H films prepared by glow discharge decomposition. The densities of photocreated dangling bonds (DBs) in the a-Si:H films after illumination of sub-bandgap pulsed light were obtained from electron spin resonance (ESR) measurements as a function of illumination time, We have obtained the lifetime resolved PL in microsecond and millisecond regions for aSi:H films by means of frequency resolved spectroscopy (FRS) before and after the illumination. The decrease in the PL intensity was not so significant as expected from the DB density. We have not found sizable change of lifetime distribution of PL after the illumination. The results suggest inhomogencity of spatial distribution of photocreated DBs. (C) 2002 Elsevier Science B.V. All rights reserved.