Annealing treatments for modified titania-silica glasses and the glasses produced by the annealing treatments. The annealing treatments include an isothermal hold that facilitates equalization of non-uniformities in fictive temperature caused by non-uniformities in modifier concentration in the glasses. The annealing treatments may also include heating the glass to a higher temperature following the isothermal hold and holding the glass at that temperature for several hours. Glasses produced by the annealing treatments exhibit high spatial uniformity of CTE, CTE slope, and fictive temperature, including in the presence of a spatially non-uniform concentration of modifier.

Systems and methods for drawing high aspect ratio metallic glass-based materials are provided. Methods of drawing a high aspect ratio metallic glass-based material are premised on stably drawing high aspect ratio metallic glass-based material from a preform metallic glass-based composition, accounting for the relationships between: the desired formation of an amorphous structure that is substantially homogenous along the majority of the length of the drawn high aspect ratio material; the desired final geometry of the drawn high aspect ratio material; the nature of the force that is used to draw the molten metallic glass-based composition; the velocity at which the high aspect ratio material is drawn; the viscosity profile of the material along its length as it is being drawn; and/or the effect of temperature on the metallic glass-based material. A precise thermal treatment is imposed along the forming length of the drawn material so as to enable a steady state drawing process, the precise thermal treatment being based on: the desire to develop a substantially same amorphous structure along the length of the drawn material; the desired final geometry for the drawn material; the nature of the force used to draw the material; the velocity at which the material is being drawn; and/or the thermal treatment's impact on the viscosity profile of the material along its length as it is being drawn.

A glass melt production apparatus, which comprises a melting vessel, a vacuum degassing apparatus, a first conducting pipe structure connecting the melting vessel and the vacuum degassing apparatus, and a second conducting pipe structure to introduce a glass melt to a forming means, provided downstream the vacuum degassing apparatus; the vacuum degassing apparatus having an uprising pipe through which the glass melt from the melting vessel ascends, a vacuum degassing vessel, and a downfalling pipe through which the glass melt from the vacuum degassing vessel descends; the flow path of the glass melt in the uprising pipe, the vacuum degassing vessel and the downfalling pipe being made of a refractory material; the first conducting pipe structure having an upstream pit to supply the glass melt to the uprising pipe; and the second conducting pipe structure having a downstream pit containing the glass melt from the downfalling pipe; the glass melt production apparatus further comprising a third conducting pipe structure connecting the upstream pit and the downstream pit; and the third conducting pipe structure having a closing means to shut off a flow of the glass melt in the third conducting pipe structure; the third conducting pipe structure or the closing means having a glass melt flow path for emergencies, which allows the glass melt to pass therethrough, depending on the height of a liquid level of the glass melt in the third conducting pipe structure in the vicinity of the closing means.

A glass melt production apparatus, which comprises a melting vessel, a vacuum degassing apparatus, a first conducting pipe structure connecting the melting vessel and the vacuum degassing apparatus, and a second conducting pipe structure to introduce a glass melt to a forming means, provided downstream the vacuum degassing apparatus; the vacuum degassing apparatus having an uprising pipe through which the glass melt from the melting vessel ascends, a vacuum degassing vessel, and a downfalling pipe through which the glass melt from the vacuum degassing vessel descends; the flow path of the glass melt in the uprising pipe, the vacuum degassing vessel and the downfalling pipe being made of a refractory material; the first conducting pipe structure having an upstream pit to supply the glass melt to the uprising pipe; and the second conducting pipe structure having a downstream pit containing the glass melt from the downfalling pipe; the glass melt production apparatus further comprising a third conducting pipe structure connecting the upstream pit and the downstream pit; and the third conducting pipe structure having a closing means to shut off a flow of the glass melt in the third conducting pipe structure; the third conducting pipe structure or the closing means having a glass melt flow path for emergencies, which allows the glass melt to pass therethrough, depending on the height of a liquid level of the glass melt in the third conducting pipe structure in the vicinity of the closing means.

To provide a method capable of producing granules without complicating the production process even if boric acid is not used. The method for producing glass raw material granules has a step of granulating, in the presence of water, a glass raw material composition (A) which comprises from 45 to 75 mass % of silica, from 3 to 30 mass % of aluminum hydroxide and from 0.4 to 4.6 mass % of an alkali metal hydroxide.

To provide a method capable of producing granules without complicating the production process even if boric acid is not used. The method for producing glass raw material granules has a step of granulating, in the presence of water, a glass raw material composition (A) which comprises from 45 to 75 mass % of silica, from 3 to 30 mass % of aluminum hydroxide and from 0.4 to 4.6 mass % of an alkali metal hydroxide.

Described herein are alkali-free, boroalumino silicate glasses exhibiting desirable physical and chemical properties for use as substrates in flat panel display devices, such as, active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting diode displays (AMOLEDs). In accordance with certain of its aspects, the glasses possess excellent compaction and stress relaxation properties.

A substrate for p-Si TFT flat panel displays made of a glass having a high low-temperature-viscosity characteristic temperature and manufactured while avoiding erosion/wear of a melting tank during melting through direct electrical heating. The glass substrate comprises 52-78 mass % of SiO.sub.2, 3-25 mass % of Al.sub.2O.sub.3, 3-15 mass % of B.sub.2O.sub.3, 3-20 mass % of RO, wherein RO is total amount of MgO, CaO, SrO, and BaO, 0.01-0.8 mass % of R.sub.2O, wherein R.sub.2O is total amount of Li.sub.2O, Na.sub.2O, and K.sub.2O, and 0-0.3 mass % of Sb.sub.2O.sub.3, and substantially does not comprise As.sub.2O.sub.3, wherein the mass ratio CaO/RO is equal to or greater than 0.65, the mass ratio (SiO.sub.2+Al.sub.2O.sub.3)/B.sub.2O.sub.3 is in a range of 7-30, and the mass ratio (SiO.sub.2+Al.sub.2O.sub.3)/RO is equal to or greater than 5. A related method involves melting glass raw materials blended to provide the glass composition; a forming step of forming the molten glass into a flat-plate glass; and an annealing step of annealing the flat-plate glass.

A substrate for p-Si TFT flat panel displays made of a glass having a high low-temperature-viscosity characteristic temperature and manufactured while avoiding erosion/wear of a melting tank during melting through direct electrical heating. The glass substrate comprises 52-78 mass % of SiO.sub.2, 3-25 mass % of Al.sub.2O.sub.3, 3-15 mass % of B.sub.2O.sub.3, 3-20 mass % of RO, wherein RO is total amount of MgO, CaO, SrO, and BaO, 0.01-0.8 mass % of R.sub.2O, wherein R.sub.2O is total amount of Li.sub.2O, Na.sub.2O, and K.sub.2O, and 0-0.3 mass % of Sb.sub.2O.sub.3, and substantially does not comprise As.sub.2O.sub.3, wherein the mass ratio CaO/RO is equal to or greater than 0.65, the mass ratio (SiO.sub.2+Al.sub.2O.sub.3)/B.sub.2O.sub.3 is in a range of 7-30, and the mass ratio (SiO.sub.2+Al.sub.2O.sub.3)/RO is equal to or greater than 5. A related method involves melting glass raw materials blended to provide the glass composition; a forming step of forming the molten glass into a flat-plate glass; and an annealing step of annealing the flat-plate glass.

Described herein are alkali-free, boroalumino silicate glasses exhibiting desirable physical and chemical properties for use as substrates in flat panel display devices, such as, active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting diode displays (AMOLEDs). In accordance with certain of its aspects, the glasses possess excellent compaction and stress relaxation properties.