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.

A glass composition comprises: 50.0 mol % to 70.0 mol % SiO.sub.2; 10.0 mol % to 25.0 mol % Al.sub.2O.sub.3; 0.0 mol % to 5.0 mol % P.sub.2O.sub.5; 0.0 mol % to 10.0 mol % B.sub.2O.sub.3; 5.0 mol % to 15.0 mol % Li.sub.2O; 1.0 mol % to 15.0 mol % Na.sub.2O; and 0.0 mol % to 1.0 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 11.0 mol % to less than or equal to 23.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 26.0 mol % to less than or equal to 40.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3—(R.sub.2O+RO))/Li.sub.2O≤0.3.

A cover glass of the present invention is characterized by including in a glass composition at least three or more components selected from SiO.sub.2, Al.sub.2O.sub.3, B.sub.2O.sub.3, Li.sub.2O, Na.sub.2O, K.sub.2O, MgO, CaO, BaO, TiC.sub.2, Y.sub.2O.sub.3, ZrO.sub.2, and P.sub.2O.sub.5, and having an X value of 7, 400 or more calculated by the following equation. The X value is a value calculated by the equation

X=61.1×[SiO.sub.2]+174.3×[Al.sub.2O.sub.3]+11.3×[B.sub.2O.sub.3]+124.7×[Li.sub.2O]−5.2×[Na.sub.2O]+226.7×[K.sub.2O]+139.4×[MgO]+117.5×[CaO]+89.6×[BaO]+191.8×[TiO.sub.2]+226.7×[Y.sub.2O.sub.3]+157.9×[ZrO.sub.2]−42.2×[P.sub.2O.sub.5].

A foldable glass substrate includes a top surface, a bottom surface, and a side surface. The side surface includes a first side surface extending at a first angle from the top surface, a second side surface extending at a second angle from the bottom surface, and a third side surface extending from each of the first side surface and the second side surface. A length of the third side surface in a direction substantially perpendicular to at least one of the top surface and the bottom surface is equal to or greater than about 0.3 times and equal to or less than about 0.7 times of a minimum distance between the top surface and the bottom surface. The minimum distance is equal to or greater than about 15 micrometers (μm) and equal to or less than about 100 μm.

One or more aspects of the disclosure pertain to an article including a film disposed on a glass substrate, which may be strengthened, where the interface between the film and the glass substrate is modified, such that the article has an improved average flexural strength, and the film retains key functional properties for its application. Some key functional properties of the film include optical, electrical and/or mechanical properties. The bridging of a crack from one of the film or the glass substrate into the other of the film or the glass substrate can be suppressed by inserting a nanoporous crack mitigating layer between the glass substrate and the film.

Glasses with compressive stress profiles that allow higher surface compression and deeper depth of layer (DOL) than is allowable in glasses with stress profiles that follow the complementary error function at a given level of stored tension. In some instances, a buried layer or local maximum of increased compression, which can alter the direction of cracking systems, is present within the depth of layer. Theses compressive stress profiles are achieved by a three step process that includes a first ion exchange step to create compressive stress and depth of layer that follows the complimentary error function, a heat treatment at a temperature below the strain point of the glass to partially relax the stresses in the glass and diffuse larger alkali ions to a greater depth, and a re-ion-exchange at short times to re-establish high compressive stress at the surface.

A foldable glass substrate includes a top surface, a bottom surface, and a side surface. The side surface includes a first side surface extending at a first angle from the top surface, a second side surface extending at a second angle from the bottom surface, and a third side surface extending from each of the first side surface and the second side surface. A length of the third side surface in a direction substantially perpendicular to at least one of the top surface and the bottom surface is equal to or greater than about 0.3 times and equal to or less than about 0.7 times of a minimum distance between the top surface and the bottom surface. The minimum distance is equal to or greater than about 15 micrometers (μm) and equal to or less than about 100 μm.

A glass-based article including a first surface and a second surface opposing the first surface defining a thickness (t) of about 3 millimeters or less (e.g., about 1 millimeter or less), and a stress profile, wherein all points of the stress profile between a thickness range from about 0.Math.t up to 0.3.Math.t and from greater than about 0.7.Math.t to t, comprise a tangent with a slope having an absolute value greater than about 0.1 MPa/micrometer. In some embodiments, the glass-based article includes a non-zero metal oxide concentration that varies along at least a portion of the thickness (e.g., 0.Math.t to about 0.3.Math.t) and a maximum central tension of less than about 71.5/√(t) (MPa). In some embodiments, the concentration of metal oxide or alkali metal oxide decreases from the first surface to a point between the first surface and the second surface and increases from the point to the second surface. The concentration of the metal oxide may be about 0.05 mol % or greater or about 0.5 mol % or greater throughout the thickness. Methods for forming such glass-based articles are also disclosed.

Glass-based articles are disclosed having a thickness in a range of from about 0.2 mm to about 4.0 mm, a first compressive stress layer extending from a first surface of the glass-based article to a first depth of compression that is in a range of from about 5% to about 20% of the thickness, a second compressive stress layer extending from a second surface of the glass-based article to a second depth of compression that is in a range of from about 5% to about 20% of the thickness, wherein the second surface is opposite the first surface, and a central region extending from the first depth of compression to the second depth of compression and having a maximum tensile stress in a range of from about 0.5 MPa to about 20 MPa. Electronic devices comprising the glass-based articles and methods of making glass-based articles are also disclosed.

A glass pharmaceutical package having a glass composition of 68.00 mol % to 81.00 mol % SiO.sub.2, from 4.00 mol % to 11.00 mol % Al.sub.2O.sub.3, from 0.10 mol % to 16.00 mol % Li.sub.2O, from 0.10 mol % to 12.00 mol % Na.sub.2O, from 0.00 mol % to 5.00 mol % K.sub.2O, from 0.10 mol % to 8.00 mol % MgO, from 0.10 mol % to 5.00 mol % CaO, from 0.00 mol % to 0.20 mol % fining agent. The glass pharmaceutical package is delamination resistant, and has class 1 or class 2 chemical durability in acid, base, and water. The glass pharmaceutical package may have a surface compressive stress of at least 350 MPa.