The subject matter described herein includes a method of manufacturing colored borosilicate glass including, preparing a raw material composition to form a homogenous powdered mixture, placing the homogenous powdered mixture in a container, heating the mixture to a temperature of 2500-3000 F., charging the container with additional homogenous powdered mixture until the container is full, melting the homogenous powdered mixture until it forms molten borosilicate glass, and refining the molten borosilicate glass between 2800-3200 F. to allow air to escape and the glass to fully homogenize.

Provided is a manufacturing method for a glass article, including: a glass melting step of continuously melting glass raw materials (Gr) in a glass melting furnace (1) by heating (electric heating) through application of a current with an electrode (11) to generate a molten glass (Gm); and a forming step of forming the molten glass (Gm) into a sheet glass by a down-draw method. The glass melting step includes adjusting a water vapor amount in an atmosphere in the glass melting furnace (1) to 15 g/Nm.sup.3 or less.

Provided is a manufacturing method for a glass article, including: a glass melting step of continuously melting glass raw materials (Gr) in a glass melting furnace (1) by heating (electric heating) through application of a current with an electrode (11) to generate a molten glass (Gm); and a forming step of forming the molten glass (Gm) into a sheet glass by a down-draw method. The glass melting step includes adjusting a water vapor amount in an atmosphere in the glass melting furnace (1) to 15 g/Nm.sup.3 or less.

A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt %, more preferably 0.001-0.010 wt %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-010. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO.sub.2. An embodiment of the invention covers a glass made according to the method.

An apparatus for manufacturing glass includes radially inner and outer flaw channels physically separated from each other by a common wall that allows heat transfer to occur between molten glass flowing through the outer flow channel and molten glass flowing in the opposite direction through the inner flow channel.

An apparatus for manufacturing glass includes radially inner and outer flaw channels physically separated from each other by a common wall that allows heat transfer to occur between molten glass flowing through the outer flow channel and molten glass flowing in the opposite direction through the inner flow channel.

A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt %, more preferably 0.001-0.010 wt %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-010. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO.sub.2. An embodiment of the invention covers a glass made according to the method.

A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt %, more preferably 0.001-0.010 wt %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-010. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO.sub.2. An embodiment of the invention covers a glass made according to the method.

Methods of producing a glass article include melting a first glass composition and feeding a second glass composition into the melter. Both glass compositions include the same combination of components but at least one component has a concentration that is different in each. At least three glass articles may be drawn from the melter, including: a first glass article formed from the first glass composition; at least one intermediate glass article composed of neither the first nor the second glass composition; and a final glass article not composed of the first glass composition. The concentration of the at least one component in the intermediate glass article may be between the concentration in the first and second glass compositions. The first glass article and final glass article may have differing values for certain properties, and the intermediate glass article may have an intermediate set of values for the same properties.

A submerged combustion melter includes a floor, a roof, and a sidewall structure connecting the floor and roof defining an internal space. A first portion of the internal space defines a melting zone, and a second portion defines a fining zone immediately downstream of the melting zone. One or more combustion burners in either the floor, roof, the sidewall structure, or any combination of these, are configured to emit the combustion gases from a position under a level of, and positioned to transfer heat to and produce, a turbulent molten mass of glass containing bubbles in the melting zone. The fining zone is devoid of combustion burners or other apparatus or components that would increase turbulence above that in the melting zone. The melter may include a treating zone that stabilizes or destabilizes bubbles and/or foam. Processes of using the melters are a feature of the disclosure.