Low expansion transparent glass ceramics

摘要

There are provided low expansion transparent glass-ceramics obtained by heat treating a base glass produced at a relatively low melting temperature of 1530° C. or below. The glass-ceramics have an average linear thermal expansion coefficient within a range from +6x10^-7/° C. to +35x10^-7/° C., 80% transmittance wavelength (T₈₀) of 700 nm or below internal transmittance of 75% or over at light wavelength of 1550 nm, heat resisting temperature of 800° C. or over and Young's modulus of 90 GPa or over. The glass-ceramics comprise SiO₂, Al₂O₃, MgO, CaO, BaO, ZnO, Li₂O, TiO₂ and ZrO₂ and contain beta-quartz or beta-quartz solid solution as a predominant crystal phase.