CRYSTALLINE GLASS MATERIAL FOR PASSIVE LASER SHUTTER AND METHOD OF PRODUCING SAID MATERIAL Russian patent published in 2010 - IPC H01S3/10 C03C4/08 

FIELD: chemistry.

SUBSTANCE: crystalline glass material for a passive laser shutter is a transparent crystalline glass lithium-alumosilicate system containing crystalline phases of a normal spinel and a β-quartz solid solution. The material has the following composition (in mol %): SiO₂ 54-73, Al₂O₃ 15-28, Li₂O 12-18, Na₂O 0-1, K₂O 0-1, ZnO 0-2, MgO 0-2, TiO₂ 4-8 and CoO 0.02-0.2. TiO₂, Na₂O, K₂O, ZnO, MgO and CoO are in amount of over 100% of the main composition. The method of producing crystalline glass material for a passive laser shutter involves melting glass material of given composition, cooling the melt and annealing it until viscosity equal to 10^10.5-10¹¹ Pa·s is attained. Two-step thermal treatment is carried out, the first of which is carried out at temperature ranging from 680 to 750°C for 2-12 hours, and the second at temperature from 760 to 820°C for 2-24 hours, and then cooling to room temperature.

EFFECT: material for passive laser shutters has low absorption saturation intensity in that wavelength range, and low coefficient of thermal expansion.

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