Method of making low expansion crystallized glass-ceramics and telescope mirror blanks made thereby

摘要

Colored and/or transparent, low expansion, crystallized glass-ceramic articles are formed by a method of thermal in situ crystallization from thermally crystallizable glass melts having lithium-containing crystals as the predominant crystalline species. The crystallized glass-ceramics produced in accordance with the method are low expansion substances, illustratively in the range of -10 to +10x10-7 per DEG C. (0 DEG -300 DEG C.). Telescope mirror blanks can be made from these transparent low expansion crystallized glass-ceramics.