According to one embodiment, a forming body of a glass forming apparatus may include an upper portion with a first forming surface and a second forming surface extending from the upper portion. The first forming surface and the second forming surface may converge at a bottom edge of the forming body. A trough for receiving molten glass may be positioned in the upper portion of the forming body. The trough may include a first weir, a second weir opposite from and spaced apart from the first weir, and a base extending between the first weir and the second weir. At least a portion of a vertical surface of the first weir may curve inward towards a centerline of the trough. Similarly, at least a portion of a vertical surface of the second weir may curve inward towards the centerline of the trough.

One aspect relates to a process for the provision of a quartz glass body, including providing a silicon dioxide granulate, making a glass melt from the silicon dioxide granulate in an oven and making a quartz glass body from at least part of the glass melt. The oven includes a hanging metal sheet crucible. One aspect also relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body which are obtainable by processing the quartz glass body further.

Provided is a glass strand that, when mixed with mortar, is less likely to decrease the fluidity of the mortar and can effectively increase the mechanical strength of a cementitious material. A glass strand includes: a plurality of glass filaments containing 12% by mass or more ZrO.sub.2 and 10% by mass or more R.sub.2O (where R represents at least one selected from Li, Na, and K); and a coating covering surfaces of the glass filaments, wherein the coating contains polyvinyl acetate resin and polyether-based urethane resin, and wherein a content of the polyether-based urethane resin in the coating is, in solid content ratio, not less than 10% by mass and not more than 90% by mass.

A method for preparing a doped optical fibre preform includes formulating, a rare earth material or a functional metal material and a co-doping agent into a doping solution, mixing a high-purity quartz powder with the doping solution, drying same at a temperature of 100C.-150C. for 12-48 hours, crushing and screening the same to obtain a doped quartz powder; depositing the doped quartz powder onto the surface of a target rod to form a doped core layer; replacing the doped quartz powder with the high-purity quartz powder, and depositing the high-purity quartz powder onto the surface of the doped core layer to form a quartz outer cladding; and removing the target rod, and gradually collapsing the entirety formed from the doped core layer and the quartz outer cladding at a high temperature to obtain the doped optical fibre preform.

An embodiment of the invention relates to an optical device which is capable of realizing a secondary nonlinear optical phenomenon. The optical device is a fiber-type optical device which is comprised of glass containing SiO.sub.2, and includes a core region, a first cladding region, and a second cladding region. At least a part of a glass region configured by the core region and the first cladding region has such a repetition structure that a first section serving as a poled crystal region and a second section serving as an amorphous region are alternately disposed along a longitudinal direction of the optical device.

A continuous sol-gel process for producing silicate-containing glasses and glass ceramics is proposed, comprising the following steps: (a) continuously feeding a silicon tetraalkoxide, a silicon alkoxide with at least one non-alcoholic functional group and an alcohol into a first reactor (R1), and at least partially hydrolyzing by the addition of a mineral acid to obtain a first product stream (A); (b) continuously providing a second product stream (B) in a second reactor (R2) by feeding a metal alkoxide component or continuously mixing an alcohol and a metal alkoxide component; (c) continuously mixing product streams (A) and (B) in a third reactor (R3) for producing a presol to obtain a third product stream (C); (d) continuously adding water or a diluted acid to the product stream (C) to obtain a sol (gelation); (e) continuously filling the emerging sol into molds to obtain an aquagel; (f) drying the aquagels to obtain xerogels; (g) sintering the xerogels to obtain silicate-containing glasses and glass ceramics.

One aspect relates to a method for the manufacture of doped quartz glass. Moreover, one aspect relates to quartz glass obtainable according to the method including providing a soot body, treating the soot body with a gas, heating an intermediate product and vitrifying an intermediate product.

A glass includes a first glass portion and a second glass portion. The first glass portion has a higher ion packing density than the second glass portion (has a composition that forms a glass in which, out of plastic deformation characteristics, plastic flow is dominant). The second glass has a lower ion packing density than the first glass portion (has a composition that forms a glass in which, out of the plastic deformation characteristics, densification is dominant).

Provided is lithium disilicate crystalline glass containing cristobalite crystal phase for high strength and aesthetic traits and its manufacturing process thereof. Exemplary embodiments of the present invention provide the high strength and aesthetic lithium disilicate crystalline glass, one kind of dental restoration materials, and its manufacturing method which induces the growth of the different crystal phase, cristobalite, from glass with lithium disilicate crystal.

A doped silica-titania glass article is provided that includes a glass article having a glass composition comprising (i) a silica-titania base glass, (ii) a fluorine dopant, and (iii) a second dopant. The fluorine dopant has a concentration of fluorine of up to 5 wt. % and the second dopant comprises one or more oxides selected from the group consisting of Al, Nb, Ta, B, Na, K, Mg, Ca and Li oxides at a total oxide concentration from 50 ppm to 6 wt. %. Further, the glass article has an expansivity slope of less than 0.5 ppb/K.sup.2 at 20 C. The second dopant can be optional. The composition of the glass article may also contain an OH concentration of less than 100 ppm.