The effect of low-temperature annealing on light emitting properties of naSi/SiOx porous column-like nanocomposite films has been studied. Influence of type of chemically active gas or inert ambient on PL characteristics is shown. Existence of metastable defects in such structures is shown. A temperature interval for healing the metastable defects is defined. Mechanisms to reduce a non-radiative recombination channel depending on the gas ambient are proposed.