A glass substrate with modified surface regions is disclosed. The glass substrate includes a first side and an opposite second side, an alkali-containing bulk disposed between the first and second sides, and a first alkali-depleted region formed in the alkali-containing bulk on the first side. The first alkali-depleted region defines at least a portion of a first topographical feature. The first topographic feature includes a height that extends in a first direction from a base portion of the first topographical feature to an outermost portion of the first topographical feature. The first direction is oriented parallel to a thickness of the glass substrate between the first and second sides. The first topographic feature also includes a width that extends in a second direction between at least two, spaced apart wall portions of the first topographical feature. The second direction is oriented normal to the first direction.

A glass substrate with modified surface regions is disclosed. The glass substrate includes an alkali-containing bulk, a first alkali-depleted region, a second alkali-depleted region, and a first ion-exchanged region. The alkali-containing bulk has a first surface and a second surface with the first and second surfaces on opposite sides. The first alkali-depleted region extends into the alkali-containing bulk from the first surface. The second alkali-depleted region extends into the alkali-containing bulk from the second surface. The first ion-exchanged region extends into the alkali-containing bulk from the first surface. The first alkali-depleted region, the second alkali-depleted region, and the first ion-exchanged region each have a substantially homogenous composition. A method of forming the glass substrate is disclosed. The method includes simultaneously forming the first alkali-depleted region and the first ion-exchanged region in the first surface. The method also includes near-simultaneously forming the second alkali-depleted region in the second surface.

A glass substrate according to one or more embodiments is disclosed. The glass substrate includes an alkali-containing bulk, at least one first alkali-depleted region, and at least one second alkali-depleted region. The alkali-containing bulk has a first surface and a second surfaces with the first and second surfaces opposing one another. The at least one first alkali-depleted region extends into the alkali-containing bulk from the first surface. The at least one second alkali-depleted region extends into the alkali-containing bulk from the second surface. The first alkali-depleted region and the second alkali-depleted region are amorphous and have a substantially homogenous composition. The first alkali-depleted region in some embodiments is a first alkali-depleted surface layer that extends across the alkali-containing bulk. The first alkali-depleted region in some embodiments is plurality of first alkali-depleted regions that are spaced apart from one another.

Disclosed herein are methods for ion exchanging, e.g., chemically strengthening, a substrate, the methods comprising applying a first electrode to at least one first region on a first surface of the substrate and applying a second electrode to at least one second region on an opposing second surface of the substrate, wherein the substrate comprises mobile ions, e.g., metal ions chosen from alkali metal ions, alkaline earth metal ions, transition metal ions, and combinations thereof; applying voltage between the first and second electrodes sufficient to cause the mobile ions to migrate away from the at least one first region on the first surface; and treating the substrate by ion exchange, e.g., chemically strengthening the substrate. Also disclosed herein are substrates, e.g., glass, glass-ceramic, and ceramic substrates, produced by the methods disclosed herein.

Embodiments of a glass substrate including an alkali-containing bulk and an alkali-depleted surface layer, including a substantially homogenous composition with at least 51 mol % Al.sub.2O.sub.3 are disclosed. In some embodiments, the alkali-depleted surface layer includes about 0.5 atomic % alkali or less. The alkali-depleted surface layer can be substantially free of hydrogen and/or crystallites. Methods for forming a glass substrate with a modified surface layer are also provided.

A glass glass-ceramic composite comprises a substrate comprising an alkali-containing glass bulk, the bulk comprising Al.sub.2O.sub.3 and SiO.sub.2 and alkali, and a glass-ceramic surface layer, the surface layer comprising an alkali-depleted glass ceramic comprising Al.sub.2O.sub.3 and SiO.sub.2 with at least 5% crystalline phase by volume, wherein the alkali-depleted glass ceramic surface layer comprises a mol % Al.sub.2O.sub.3 of at least 51%. A method of preparing the composite is also disclosed.

A glass article includes a first surface, a second surface which is opposite the first surface, a first compressive region which extends to a first compression depth in a thickness direction from the first surface, a second compressive region which extends to a second compression depth from the second surface, and a tensile region which is disposed between the first compressive region and the second compressive region. A stress profile of the first compressive region includes a first point and a first inflection point, the first inflection point is located between the first point and the first surface, a depth from the first surface to the first point is 45 to 55% of the first compression depth from the first surface, stress at the first point is greater than 50% of compressive stress of the first surface, and a thickness of the glass article is 0.01 to 0.05 mm.

A method of forming a graphene device includes: providing a glass substrate with a blocking layer disposed thereon to form a stack; providing a first electrode and a second electrode; increasing the temperature of the stack to at least 100° C.; applying an external electric field (V.sub.P) to the first electrode such that at least one metal ion of the glass substrate migrates toward the first electrode to create a depletion region in the glass substrate adjacent the second electrode; decreasing the temperature of the stack to room temperature while applying the external electric field to the first electrode; and after reaching room temperature, setting the external electric field to zero to create a frozen voltage region adjacent the second electrode.

A light guide plate that includes a glass substrate including an edge surface and at least two major surfaces defining a thickness and an edge surface, the edge surface configured to receive light from a light source and the glass substrate configured to distribute the light from the light source, wherein the glass substrate comprises an alkali-containing bulk and an alkali-depleted surface layer, the alkali-depleted surface layer comprising about 0.5 atomic % alkali or less. Display products and methods of processing a glass substrate for use as a light guide plate are also provided.

An apparatus for continuous electro-thermal poling of glass or glass ceramic material, includes a lower support conveying and contacting electrode structure, an upper contacting electrode structure positioned above the lower support structure, and one or more DC bias voltage sources connected to one or both of the upper contacting structure and the lower support structure. A process for continuous electro-thermal poling of glass or glass ceramic sheets or substrates includes heating the sheet or substrate, feeding the sheet or substrate continuously or continually, while applying a DC voltage bias, and cooling the sheet or substrate to within 0-30° C. of ambient temperature.