The transformation of local structure in silica and alkali-borosilicate glasses at separate and combined influence of radiation and high temperature

At present a great attention is paid to processes accompanied by breaking and switching of valent bonds in glassy compounds. Most processes including creation and transformation of radiation defects are explained by these phenomena. For instance, breaking of Si-O bonds followed by rebuilding of glass structure is the dominating mechanism of defect formation in fused silica under g-ray and electronic irradiation. No atom displacements occur, i.e. removing of bridge oxygen by elastic scattering of initial or Compton electrons. Thus, local rebuilding of glass structure is allowed under valent-configuration transformations.This paper concernts to the phenomena occuring in silica and alkali-borosilicate glasses under separate and combined influence of radiation and high temperature. Various well-known aluminium and boron centres were used as probes to study the local changes in glass structure. It is shown in the work that the transformation of aluminium and boron centres occurr in glass structure under irradiation of fused silica by high doses of ''6''0Co g- rays and n + g flux, as well as under high temperature processing of the samples in the g-field. The mechanism is suggested for the explanation of such changes by transformations of aluminum and boron centres by means of valence bond switch causing valence-configuration change