One aspect is a method for producing a multilayered silica glass body. The method involves producing a multilayered silica glass body in which a transparent silica glass layer is provided on the surface of a siliceous substrate made of a siliceous material. The method includes preparing the siliceous substrate, preparing a silica slurry in which silica particles are dispersed in a liquid, applying the silica slurry to the surface of the siliceous substrate, leveling the silica slurry applied to the surface of the siliceous substrate by applying vibration to the siliceous substrate, drying the leveled silica slurry, and vitrifying the dried silica slurry by heating to form a transparent silica glass layer. As a result, a transparent silica glass layer of uniform thickness is obtained at excellent yield, and a method for producing a multilayered silica glass body easily in a short time is provided.

One aspect is a method for producing a multilayered silica glass body. The method involves producing a multilayered silica glass body in which a transparent silica glass layer is provided on the surface of a siliceous substrate made of a siliceous material. The method includes preparing the siliceous substrate, preparing a silica slurry in which silica particles are dispersed in a liquid, applying the silica slurry to the surface of the siliceous substrate, leveling the silica slurry applied to the surface of the siliceous substrate by applying vibration to the siliceous substrate, drying the leveled silica slurry, and vitrifying the dried silica slurry by heating to form a transparent silica glass layer. As a result, a transparent silica glass layer of uniform thickness is obtained at excellent yield, and a method for producing a multilayered silica glass body easily in a short time is provided.

The present invention provides a glass composition including, as components, in mol %: 50 to 70% SiO.sub.2; 10 to 20% Al.sub.2O.sub.3; 2 to 5% MgO; 3 to 15% CaO; 3 to 15% Li.sub.2O; 3 to 15% Na.sub.2O; and 0 to 5% K.sub.2O, wherein when a content of a component X in mol % is expressed as [X], [Al.sub.2O.sub.3]— [R.sub.2O] is less than −0.5%, where [R.sub.2O] is the sum of [Li.sub.2O], [Na.sub.2O], and [K.sub.2O].

Apparatus and methods are disclosed for forming a glass article in which molten glass is heated in a refractory vessel by establishing an electrical current in the molten glass between opposing powered electrodes along a first electrical path. The melting vessel includes a precious metal component in contact with the molten glass, and at least one non-powered electrode proximate the precious metal component. The at least one non-powered electrode and the precious metal component form second and third electrical paths, respectively, in parallel with the first electrical path such that an electrical current in the second electrical path is decreased, thereby reducing an electrochemical reaction in the precious metal component.

Apparatus and methods are disclosed for forming a glass article in which molten glass is heated in a refractory vessel by establishing an electrical current in the molten glass between opposing powered electrodes along a first electrical path. The melting vessel includes a precious metal component in contact with the molten glass, and at least one non-powered electrode proximate the precious metal component. The at least one non-powered electrode and the precious metal component form second and third electrical paths, respectively, in parallel with the first electrical path such that an electrical current in the second electrical path is decreased, thereby reducing an electrochemical reaction in the precious metal component.

A method of making glass having a basic soda-lime-silica glass portion, and a colorant portion, the colorant portion including total iron as Fe.sub.2O.sub.3 in the range of at least 0.00 to no more than 0.02 weight percent, a redox ratio in the range of 0.35 to 0.6, and tin metal providing tin in an amount within the range of greater than 0.005 to 5.0 weight percent; the glass product has a tin side and an opposite air side, said tin side of the glass having a higher concentration of tin than the air side, the air side having a uniform concentration of tin from the air side of the glass product towards the tin side of the glass product.

A method of making glass having a basic soda-lime-silica glass portion, and a colorant portion, the colorant portion including total iron as Fe.sub.2O.sub.3 in the range of at least 0.00 to no more than 0.02 weight percent, a redox ratio in the range of 0.35 to 0.6, and tin metal providing tin in an amount within the range of greater than 0.005 to 5.0 weight percent; the glass product has a tin side and an opposite air side, said tin side of the glass having a higher concentration of tin than the air side, the air side having a uniform concentration of tin from the air side of the glass product towards the tin side of the glass product.

Thin glass substrates are provided. Also provided are methods and apparatuses for the production thereof and provides a thin glass substrate of improved optical quality. The method includes, after the melting and before a hot forming process, adjusting the viscosity of the glass that is to be formed or has at least partially been formed is in a defined manner for the thin glass substrate to be obtained. The apparatus includes a device for melting, a device for hot forming, and also a device for defined adjustment of the viscosity of the glass to be formed into a thin glass substrate, and the device for defined adjustment of the viscosity of the glass to be formed into a thin glass substrate is arranged upstream of the device for hot forming.

Thin glass substrates are provided. Also provided are methods and apparatuses for the production thereof and provides a thin glass substrate of improved optical quality. The method includes, after the melting and before a hot forming process, adjusting the viscosity of the glass that is to be formed or has at least partially been formed is in a defined manner for the thin glass substrate to be obtained. The apparatus includes a device for melting, a device for hot forming, and also a device for defined adjustment of the viscosity of the glass to be formed into a thin glass substrate, and the device for defined adjustment of the viscosity of the glass to be formed into a thin glass substrate is arranged upstream of the device for hot forming.

A float glass system includes a float bath having an entrance end and an exit end. At least one machine vision camera is located to view an interior of the float bath. At least one sensor is connected to the float bath to measure an operating parameter of the float bath. At least one operating device is connected to the float bath. The at least one machine vision camera, the at least one sensor, and the at least one operating device are connected to a control system configured to control the operating device based on input from the at least one machine vision camera and/or the at least one sensor.