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EPR measurements of HFS of nuclei lH, 2D in spectra of quartz glasses and 29Si in spectra of high-silicate glasses have been made and analysed. A stochastic model for the y-radiation-induced paramagnetic centres are suggested. Calculations of the electronic structure of the unit AB, have been carried out and a correlation diagram between the orbitals possible for tetrahedral (Td) and pyramidal (C3") configurations has been obtained. This enables one to make comments on the EPR spectra of the units SiO2-and ROSiO:-. a n p~s e c~o i i (Td) H n q a m n a n m o i i (C3") KoH@arypawCi nocTpoeaa. TO HaeT I . IntrodiictionWhen studying the hyperfine structure (HFS) in electron paramagnetic resonance (EPR) spectra of quartz glasses it was shown that different doublets of hyperfine structure observed in EPR spectra and previously attributed to 29Si nuclei could be associated with protons [l, 21 rather than 29Si nuclei. Naturally, the way of hydrogen entry into a glass network depends highly on the technological process of glass preparation and batch purity. It seems therefore that two HFS doublets with splitting from 5 to 10 G [3] were found by Weeks in some cases and were not found in others [4]. The above doublets slightly differ in HI? splitting which are identified as 7 and 8 G in [3] or 8 and 9 G i n [5]. The two latter and the three other doublets having a splitting of about 1 G were observed in crystalline quartz [3,4]. Their appearance was explained by exchange interactions of an unpaired electron through oxygen with 29Si nuclei, existing in structural units close to the paramagnetic E' centre. This explanation was suggested by Silsbee [5]. When explaining E P R measurements Weeks [4] and many other authors take into account the 29Si nuclei and hardly the existence of hydrogen in different structural positions. It is highly important to take into account the way of hydrogen entry into the glass network for the analysis of the causes conditioning the changes of the H F splitting values of hydrogen doublets. I n fact, the doublets presenting proton HFS were identified from E P R spectra, and it was established that the HF splitting depended on the kind of impurities co-existing with hydrogen [l, 2, 6 to 81. The actuality of further studies of hydrogen doublets was noted a t the X. International Congress on Glass [9]. This paper is devoted to the investigation of HFS doublets of magnetic silicon and hydrogen nuclei in silicate and quartz glasses.