Polymerization of tetraethoxysilane on a glass substrate was investigated by remote microwave plasma using argon with portions of nitrous oxide as carrier gas. Transparent layer like a thickness of 0.5 ${mu}m$ 3 ${mu}m$ were obtained, differing in chemical composition, depending on plasma power and treatment time as well as on ageing time. In general the milder the treatment and the shorter the ageing was, the higher was the content of organic structural elements in the layer. We have identified that the chemical structure of our samples composed of mainly Si O and Si C groups containing aliphatics, carbonyl groups. These results were obtained by X ray photon spectroscopy, Fourier transformed infrared spectroscopy, and scanning electron microscope combined with Energy dispersive X ray spectroscopy.