Features of Formation of Optically Transparent Nanostructured Spinel-Containing Glass-Ceramic Materials

The main conditions for the formation of the sitallized nanostructure of glass-ceramic materials based on spinel containing Co²⁺ ions with high absorption in the range of 1.6–1.7 μm for laser shutters operating in the mode of passive Q-switched are determined: the presence of phase-forming oxides (MgO, Al₂O₃)≥40.0 wt.%, glass-forming oxides (B₂O₃, SiO₂) ≥54.0 wt.%, crystallization catalysts (P₂O₅, ZnO, ZrO₂, TiO₂, CeO₂, Sb₂O₃) ≤4.9 wt.%, modifying additives (SrO, BaO, СaO, CoO)≤1.1 wt.%; glass melting at a temperature of 1550°C for 6 hours; three-stage heat treatment (I stage—800°C, 1 h; II stage—900°C, 30 min; III stage—950°C, 5 min). As established, ensuring high values of light transmission (Т≥74%) and crack resistance (K_1C≥5.0 MPa·m^1/2) of glass-ceramic material is realized due to the following stages: metastable phase immiscibility by the mechanism of spinodal decomposition (800°C), intensification of nucleation (850°C) while keeping the bidispersity of the system and providing the structural stability of the glass with kinetic inhibition of the crystal growth process under conditions of high viscosity, formation of solid solutions with the structure of high-temperature quartz in the low-temperature region (900°C) and spinel crystals of ~50 nm in size in the amount of ~50 vol.% (950°C) with a regular distribution of nanocrystals in the residual glass phase.