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.

A borosilicate glass for a pharmaceutical container having high appearance quality, particularly a small number of air lines, and a glass tube for a pharmaceutical container are provided. The borosilicate glass for a pharmaceutical container contains, in mass %, from 70.0 to 78.0% of SiO.sub.2, from 5.0 to 8.0% of Al.sub.2O.sub.3, from 5.0 to 12.0% of B.sub.2O.sub.3, from 0 to 4.0% of CaO, from 0 to 4.0% of BaO, from 4.0 to 8.0% of Na.sub.2O, from 0 to 5.0% of K.sub.2O and from 0.001 to 1.0% of SnO.sub.2.

The invention relates to a process for producing alkali metal-rich aluminosilicate glasses having a content (in mol % based on oxide) of alkali metal oxides of 4-16 mol %, of Al.sub.2O.sub.3 of at least 4 mol % and of B.sub.2O.sub.3 of 0-4 mol %, wherein 0.15 mol % to 0.9 mol % of chloride(s) and at least one refining agent from the group of sulfate(s) (reported as SO.sub.3), CeO.sub.2 are added to the glass batch and wherein the sum total of refining agents added in the batch is 0.17 mol % to 1.3 mol %.

Disclosed herein are methods for making glass, comprising forming a slurry comprising at least one fining agent; adjusting the pH of the slurry to a value ranging from about 3 to about 12; combining the slurry with glass batch materials to form a batch composition; and melting the batch composition. Methods for reducing agglomerates in a glass melt are also disclosed herein. Further disclosed herein are systems for making glass, the systems comprising a pre-mixing vessel for preparing a slurry comprising at least one fining agent; an ultrasonic vessel for applying ultrasonic energy to the slurry; a mixing vessel for combining the slurry with glass batch materials to form a batch composition; and a melting vessel for melting the batch composition.

A useable particulate nepheline syenite having a grain size to provide an Einlehner Abrasive Value of less than about 100 is described. The particulate nepheline syenite is generally free from agglomeration and moisture free. At least 99% of the nepheline syenite particles have a size less than 10 microns.

A fining agent for reducing the concentration of seeds or bubbles in a silicate glass. The fining agent includes at least one inorganic compound, such as a hydrate or a hydroxide that acts as a source of water. In one embodiment, the fining agent further includes at least one multivalent metal oxide and, optionally, an oxidizer. A fusion formable and ion exchangeable silicate glass having a seed concentration of less than about 1 seed/cm.sup.3 is also provided. Methods of reducing the seed concentration of a silicate glass, and a method of making a silicate glass having a seed concentration of less than about 1 seed/cm.sup.3 are also described.

A pink aluminosilicate glass, comprising: a glass former, a network intermediate oxide, a network modifier oxide, a network former oxide, a network modifier, a colorant and a clarificant, wherein the glass former is SiO.sub.2, the network modifier oxide is CaO, MgO, K.sub.2O and Na.sub.2O, the network former oxide is B.sub.2O.sub.3, and the network modifier is ZrO.sub.2 and SrO. This glass is pink in visible light, has a good visual effect, and has a relatively high thermal stability, and can improve the usage safety in harsh working environments.

A fining agent for reducing the concentration of seeds or bubbles in a silicate glass. The fining agent includes at least one inorganic compound, such as a hydrate or a hydroxide that acts as a source of water. In one embodiment, the fining agent further includes at least one multivalent metal oxide and, optionally, an oxidizer. A fusion formable and ion exchangeable silicate glass having a seed concentration of less than about 1 seed/cm.sup.3 is also provided. Methods of reducing the seed concentration of a silicate glass, and a method of making a silicate glass having a seed concentration of less than about 1 seed/cm.sup.3 are also described.

According to some embodiments, there is provided herein a glass composition comprising Polyhalite.