LASER-INDUCED FORMATION OF PARAMAGNETIC CENTERS IN HYDROGEN-CONTAINING QUARTZ GLASSES

It was found that hydrogen-containing H(I)- and H(II)-centers are crea ted under UV laser irradiation (E = 5 and 6.4 eV) in quartz glasses co ntaining impurity hydrogen and oxygen-deficient centers. It was shown that oxygen-deficient centers are not major precursors of the II-cente rs, unlike in the case of gamma-induced processes (a Co-60 source, E = 1.25 MeV). The mechanism is suggested of laser-induced formation of h ydrogen-containing centers by transformation of hydrogen-bonded oxygen -deficient sites (structure of the type =Si-HH-Si), displaying no abso rption bands in the UV-spectral region. The experiments were also carr ied out with laser-irradiated samples saturated with molecular hydroge n (P = 5 MPa, T = 300 K, 14 days). It is the H-2 molecules that intera ct efficiently with both oxygen-deficient centers and E'-center-type r adicals.