[en] Aim of the inquiry: Revealing peculiarities of formation, decay and transformation of defects and viscosity glass changes at separate and combined influence of radiation and high temperatures on silica glass with different degree of disorder. Method of inquiry: Spectra of optical absorption, photoluminescence, dose dependence of the different characteristics, annealing of radiation defects at ambient and high temperature (in the range 50-650 deg.C) irradiation of quartz mono blocks and tubes, activation analysis of impurity content and calculation of activation energy. The results achieved and their novelty: The nature of new defect was determined. Peculiarity of formation, decay and transformation of radiation defects at separate and combined influence of radiation and high temperatures were found. The activation energy of oxygen vacancies annealing was determined. Decreasing the silica glass softening point at increase of ionizing radiation power was theoretically justified. (author)