Hydrogenated polysilane films prepared from a SiH4 plasma were oxidized at room temperature and subsequently annealed at temperatures ranging from 800 to 1000 degrees C. It is found that the 1000 degrees C annealed films consist of Si nanocrystallites embedded in SiO2 and exhibit stable intense luminescence peaked at 1.5 eV under 488 nm excitation at room temperature. On the basis of the temperature and excitation power dependences of the steady-state and time-resolved luminescence from the annealed films, radiative recombination is thought to occur through localized states in the Si/SiO2 interface region.