Mechanical properties, strength physics and plasticity

Evolution of point and structural defects in silica glass treated with fine annealing

I. P. Shcherbakov^a, S. B. Eronko^b, M. F. Kireenko^a, L. V. Tikhonova^a, A. E. Chmel<sup>a

a</sup> Ioffe Institute, St. Petersburg, Russia
^b S. I. Vavilov State Optical Institute, St. Petersburg, Russia

Abstract: The silica glass with a high content of OH groups was synthesized by the high-temperature hydrolysis of SiCl$_4$ in a flame of oxyhydrogen torch and subjected to fine annealing. A combination of the photoluminescence and IR reflection spectroscopy was applied to assess the evolution of the ensemble of structural defects in the bulk and surface layer over the course of annealing carried out at 480$^\circ$C. The marked decrease of the defect concentration was observed in the bulk at all time expositions in the range 2 to 72 hours. However, in a thin surface layer, the decrease of the concentration of silanol groups Si–OH formed in the process of synthesis was detected. Decay of these groups results in the silicate network consolidation that led to the forming of the superficial layer characterized by an elevated microhardness.

Keywords: silica glass, fine annealing, photoluminescence, IR transmission.

Received: 22.05.2023
Revised: 22.05.2023
Accepted: 26.06.2023

DOI: 10.21883/FTT.2023.08.56157.85

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