Plasma chemical methods of deposition are widely used for optical glass synthesis and fiber preforms fabrication. Peculiarity of such glass deposition is simultaneous oxidation in plasma of the chlorides necessary for obtaining desired composition of the glass. Experimental study of kinetics of plasma chemical processes, accompanying deposition presents lots of difficulties because of the variety of the processes and difficulties in high rate registration of chemical components.In the experiments we used a setup for optical fiber preforms synthesis in surface microwave-induced discharge total pressure being several torr (SPCVD technology). The high velocity of reagents passing the substrate tube made it possible to register concentrations of chemical components as a function of the coordinate along the plasma column, instead of just registering the same values as a function of time. To do that the image of the selected point of the plasma column was collected on the input slit of spectrometer for lines intensity registration. Although, the given method does not permit to measure absolute concentrations of the components under study, the kinetics of the chemical reactions without interfering into the process can be found. In Ge-, Al-, Er doping we observed spatial separating of monoxides (SiO, GeO, AlO, ErO) along the tube. It can be explained by exchange reaction influence: . Whereas glass is formed as the result of heterogeneous process, when the appeared monoxides adsorb by the surface, and then are completely oxidized on it to form the glass, deposition concentration profile corresponds to the longitudinal profile of appearing monoxide in the plasma column. Hence, we can speak about longitudinal spatial separation of the deposition zones. It is proved by the analysis of the glass specimens obtained. When periodical scanning such a multi-component deposition zone along the substrate a periodical lamination of glass composition with period 10-500 nm is observed.