This paper compares photbluminescence optical absorption, H-evolution, and infrared vibrational spectra of glow-discharge deposited hydrogenated amorphous silicon, a-Si:H, prepared in three different ways: continuous deposition and deposition interrupted hundreds of times either by a shutter or by shutting off the plasma power. The latter yields an excess hydrogen content, a blue shift of the optical gap, and a decrease in the photoluminescence intensity. The results are related to the initial non-equilibrium plasma chemistry.