To provide a crystallized glass substrate including a surface with a compressive stress layer, where 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 a central stress CT determined by using curve analysis is 55 to 300 MPa.

According to one embodiment, a glass may include from about 50 mol. % to about 70 mol. % SiO.sub.2; from about 12 mol. % to about 35 mol. % B.sub.2O.sub.3; from about 4 mol. % to about 12 mol. % Al.sub.2O.sub.3; greater than 0 mol. % and less than or equal to 1 mol. % alkali metal oxide, wherein Li.sub.2O is greater than or equal to about 20% of the alkali metal oxide; from about 0.3 mol. % to about 0.7 mol. % of Na.sub.2O or Li.sub.2O; and greater than 0 mol. % and less than 12 mol. % of total divalent oxide, wherein the total divalent oxide includes at least one of CaO, MgO and SrO, and wherein a ratio of Li.sub.2O (mol. %) to (Li.sub.2O (mol. %)+(Na.sub.2O (mol. %)) is greater than or equal 0.4 and less than or equal to 0.6. The glass may have a relatively low high temperature resistivity and a relatively high low temperature resistivity.

According to one embodiment, a glass may include from about 50 mol. % to about 70 mol. % SiO.sub.2; from about 12 mol. % to about 35 mol. % B.sub.2O.sub.3; from about 4 mol. % to about 12 mol. % Al.sub.2O.sub.3; greater than 0 mol. % and less than or equal to 1 mol. % alkali metal oxide, wherein Li.sub.2O is greater than or equal to about 20% of the alkali metal oxide; from about 0.3 mol. % to about 0.7 mol. % of Na.sub.2O or Li.sub.2O; and greater than 0 mol. % and less than 12 mol. % of total divalent oxide, wherein the total divalent oxide includes at least one of CaO, MgO and SrO, and wherein a ratio of Li.sub.2O (mol. %) to (Li.sub.2O (mol. %)+(Na.sub.2O (mol. %)) is greater than or equal 0.4 and less than or equal to 0.6. The glass may have a relatively low high temperature resistivity and a relatively high low temperature resistivity.

An article comprises a glass substrate. The glass substrate has a first surface having a plurality of vias therein, and a second surface parallel to the first surface. At least one of the first surface and the second surface is an etched surface having a surface roughness (Ra) of 0.75 nm or less. The glass substrate comprises, in mol percent on an oxide basis: 65 mol %≤SiO.sub.2≤75 mol %; 7 mol %≤Al.sub.2O.sub.3≤15 mol %; 26.25 mol %≤RO+Al.sub.2O.sub.3−B.sub.2O.sub.3; 0 mol %≤R.sub.2O≤2 mol %. RO=MgO+CaO+SrO+BaO+ZnO. R.sub.2O=Li.sub.2O+Na.sub.2O+K.sub.2O+Rb.sub.2O+Cs.sub.2O.

An article comprises a glass substrate. The glass substrate has a first surface having a plurality of vias therein, and a second surface parallel to the first surface. At least one of the first surface and the second surface is an etched surface having a surface roughness (Ra) of 0.75 nm or less. The glass substrate comprises, in mol percent on an oxide basis: 65 mol %≤SiO.sub.2≤75 mol %; 7 mol %≤Al.sub.2O.sub.3≤15 mol %; 26.25 mol %≤RO+Al.sub.2O.sub.3−B.sub.2O.sub.3; 0 mol %≤R.sub.2O≤2 mol %. RO=MgO+CaO+SrO+BaO+ZnO. R.sub.2O=Li.sub.2O+Na.sub.2O+K.sub.2O+Rb.sub.2O+Cs.sub.2O.

The embodiments described herein relate to low temperature moldable sheet forming glass compositions and glass articles formed from the same. In various embodiments, the glass composition comprises from about 60 mol. % to about 67 mol. % SiO.sub.2, from about 6 mol. % to about 11 mol. % B.sub.2O.sub.3, from about 4.5 mol. % to about 11 mol. % Li.sub.2O, Al.sub.2O.sub.3, Na.sub.2O, and K.sub.2O. The glass composition also includes greater than about 2 mol. % RO, where RO are divalent metal oxides, and R.sub.2O from about 14 mol. % to about 20 mol. %, where R.sub.2O are alkali metal oxides. The glass composition also has a glass transition temperature T.sub.g of less than about 500 C, a softening point of less than about 650 C, and a coefficient of thermal expansion (CTE) of less than about 85×10.sup.−7 K.sup.−1.

The embodiments described herein relate to low temperature moldable sheet forming glass compositions and glass articles formed from the same. In various embodiments, the glass composition comprises from about 60 mol. % to about 67 mol. % SiO.sub.2, from about 6 mol. % to about 11 mol. % B.sub.2O.sub.3, from about 4.5 mol. % to about 11 mol. % Li.sub.2O, Al.sub.2O.sub.3, Na.sub.2O, and K.sub.2O. The glass composition also includes greater than about 2 mol. % RO, where RO are divalent metal oxides, and R.sub.2O from about 14 mol. % to about 20 mol. %, where R.sub.2O are alkali metal oxides. The glass composition also has a glass transition temperature T.sub.g of less than about 500 C, a softening point of less than about 650 C, and a coefficient of thermal expansion (CTE) of less than about 85×10.sup.−7 K.sup.−1.

Embodiments of 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 0.7.Math.t, comprise a tangent that is less than about −0.1 MPa/micrometers or greater than about 0.1 MPa/micrometers, are disclosed. 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). 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.

Embodiments of 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 0.7.Math.t, comprise a tangent that is less than about −0.1 MPa/micrometers or greater than about 0.1 MPa/micrometers, are disclosed. 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). 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.

Methods for strengthening edges of a laminated glass article comprising a glass core layer positioned between a first glass clad layer and a second glass clad layer are disclosed. The methods may comprise polishing the cut edges of the laminated glass article with a slurry of polishing media applied to the edges of the laminated glass article with brushes. An edge strength of the laminated glass article is greater than or equal to about 400 MPa after polishing.