The present invention relates to a chemically strengthened glass having a thickness of t [mm], and having a profile of a stress value CS.sub.x [MPa,] at a depth x [.Math.m] from a surface of the glass, the stress value being measured by a scattered-light photoelastic stress meter, in which a second-order differential value CS.sub.x" of the stress value CS.sub.x in the profile satisfies the following expression within a range of CS.sub.x≥0: 0<CS.sub.x"≤0.050.

Optically transparent glass ceramic materials comprising a glass phase containing and a crystalline tungsten bronze phase comprising nanoparticles and having the formula M.sub.xWO.sub.3, where M includes at least one H, Li, Na, K, Rb, Cs, Ca, Sr, Ba, Zn, Cu, Ag, Sn, Cd, In, Tl, Pb, Bi, Th, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and U, and where 0<x<1. Aluminosilicate and zinc-bismuth-borate glasses comprising at least one of Sm.sub.2O.sub.3, Pr.sub.2O.sub.3, and Er.sub.2O.sub.3 are also provided.

A near-infrared absorbing glass is provided and includes 10% to 40% by weight of phosphorus and 5% to 35% by weight of iron, where a molar ratio of phosphorus to iron (P/Fe) of the near-infrared absorbing glass is between 1.75 and 5, and the near-infrared absorbing glass has an average transmittance of less than 10% to light with wavelengths ranging from 930 nm to 950 nm. A near-infrared cut-off filter including the near-infrared absorbing glass is also provided.

A composition includes 30 mol % to 60 mol % SiO.sub.2; 15 mol % to 40 mol % Al.sub.2O.sub.3; 5 mol % to 25 mol % Y.sub.2O.sub.3; 5 mol % to 15 mol % TiO.sub.2; and 0.1 mol % to 15 mol % RO, such that RO is a sum of MgO, CaO, SrO, and BaO.

To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOL.sub.zero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 μm, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOL.sub.zero, which is a product of the compressive stress CS on the outermost surface and the stress depth DOL.sub.zero (μm), is 4.8×10.sup.4 or more.

Provided is a Li.sub.2O-Al.sub.2O.sub.3-SiO.sub.2-based crystallized glass that has a high permeability to light in a ultraviolet to infrared range and is less likely to be broken. A Li.sub.2O-Al.sub.2O.sub.3-SiO.sub.2-based crystallized glass contains, in terms of % by mass, 40 to 90% Si.sub.O2, 5 to 30% Al.sub.2O.sub.3, 1 to 10% Li.sub.2O, 0 to 20% SnO.sub.2, 0 to 5% ZrO.sub.2, 0 to 10% MgO, 0 to 10% P.sub.2O.sub.5, and 0 to 4% TiO.sub.2 and a mass ratio of Li.sub.2O/(MgO+CaO+SrO+BaO+Na.sub.2O+K.sub.2O) is 3 or less.

The present invention relates to a chemically strengthened glass ceramic including a crystalline phase, having two main surfaces opposed to each other, and including an amorphized region in a surface layer of at least one of the main surfaces and a crystallized region inside the glass, in which the amorphized region has a crystallinity of 10 vol % or less at a depth of 100 nm from an outermost surface of the glass.

A glass ceramic includes feldspar crystal phases, non-crystalline glass phases, Al.sub.2O.sub.3 phases, and SiO.sub.2 phases. At least one pair of the Al.sub.2O.sub.3 phases is bonded via at least one of the feldspar crystal phases.

A glass-ceramic component is provided that has a low average coefficient of thermal expansion (CTE) and a high CTE homogeneity. The use of such a component and a process for producing such a component are also provided.

The present invention relates to a glass including, in terms of mole percentage based on oxides: 52% to 70% of SiO.sub.2; 14% to 25% of Al.sub.2O.sub.3; 10% to 18% of Li.sub.2O; 1% to 7% of Na.sub.2O; 0.1% to 5% of K.sub.2O; 0% to 10% of B.sub.2O.sub.3; 0% to 5% of P.sub.2O.sub.5; 0% to 5% of MgO; 0% to 5% of ZnO; 0% to 2% of ZrO.sub.2; and 0% to 5% of Y.sub.2O.sub.3, in which a parameter M is 20 or less, the parameter M being determined by the following formula, M=−1.15×[SiO.sub.2]−1.73×[Al.sub.2O.sub.3]+0.155×[Li.sub.2O]+0.74×[Na.sub.2O]−4.75×[K.sub.2O]−2.1×[B.sub.2O.sub.3]−2.17×[P.sub.2O.sub.5]+3.25×[MgO]−2.0×[ZnO]−13.3×[ZrO.sub.2]−0.80×[Y.sub.2O.sub.3]+120.