A quartz glass provides an opaque quartz glass having high light-shielding property, excellent mechanical strength and excellent cleaning resistance against hydrofluoric acid. By setting the maximum width of the amorphous bubbles existing in the opaque quartz glass to an average of 3 to 15 m and the density to 2.15 g/cm.sup.3 or more, the mechanical strength after baking and the cleaning resistance by hydrofluoric acid are improved. The opaque quartz glass has a whiteness at a thickness of 10 mm of 75 to 90%, the reflectance of light with a wavelength of 0.24 to 2.6 m at a thickness of 4 mm is 60 to 85%, and the bending strength after baking is 95 MPa. In addition, a foaming agent may be mixed in the opaque quartz glass. An opaque quartz glass having cleaning resistance against acid can be obtained.

A glass including silica and titania is disclosed. An average hydroxyl concentration of a plurality segments of the glass is in a range from about 20 ppm to about 450 ppm, an average titania concentration of the plurality of segments is in a range from about 6 wt. % to about 12 wt. %, and each segment of the plurality of segments has a length of about 12.7 mm, a width of about 12.7 mm, and a height of about 7.62 mm. The hydroxyl concentration of each segment is measured using a Fourier transform infrared spectroscopy in transmission, the refractive index is measured using an optical interferometer with a 633 nm operating wavelength and a resolution of 270 microns270 microns pixel size, and the average titania concentration is determined based upon the measured refractive index.

The present disclosure provides a method for fabrication of a glass preform. The method includes production of soot particles in a combustion chamber using a precursor material. The heating of the precursor material produces the soot particles along with one or more impurities. In addition, the method includes agglomeration of the soot particles. Further, the method includes separation of the soot particles from the one or more impurities. Also, the separation of the soot particles is performed in a cyclone separator. Furthermore, the method includes collection of the soot particles. Also, the soot particles are compacted with facilitation of a preform compaction chamber. Also, the compacted preform is sintered with facilitation of a sintering furnace. The compaction of the soot particles followed by sintering results in formation of the glass preform.

A method for forming an optical quality glass is provided. The method includes contacting silica soot particles with a hygroscopic additive, forming a silica soot compact, and removing the hygroscopic additive from the silica soot compact. A method of forming a cladding portion of an optical fiber preform is also provided.

A formulation usable to produce plates and shaped bodies has a base slip, quartz glass particles and multicomponent glass particles that are crystallizable or at least partly crystallized. The base slip contains water as dispersion medium with a content between 30% and 50% by weight and ultrafine SiO.sub.2 particles distributed, preferably colloidally therein, with a proportion between 50% and 70% by weight. The proportion of quartz glass particles in the formulation is in the range from 40% to 70% by weight and the proportion the multicomponent glass particles in the formulation is in the range from 5% to 37% by weight. The formulation can be used in a composite material. Firing aids can be made from the composite material.

A method for loading a blank composed of fused silica with hydrogen, including loading the blank at a first temperature (T.sub.1) and a first hydrogen partial pressure (p.sub.1), and further loading the blank at a second temperature (T.sub.2) which is different from the first temperature and at a second hydrogen partial pressure (p.sub.2) which is different from the first hydrogen partial pressure. The first and second temperatures (T.sub.1, T.sub.2) are lower than a limit temperature (T.sub.L) at which a thermal formation of silane in the fused silica of the blank commences. Also disclosed are a lens element produced from such a blank and a projection lens that includes at least one such lens element.

A glass composite for use in Extreme Ultra-Violet Lithography (EUVL) is provided. The glass composite includes a first silica-titania glass section. The glass composite further includes a second doped silica-titania glass section mechanically bonded to a surface of the first silica-titania glass section, wherein the second doped silica-titania glass section has a thickness of greater than about 1.0 inch.

The present invention provides a composite shaped body comprising silica nanoparticles and an organic polymer, wherein the silica nanoparticles and the organic polymer form a three-dimensional network; thereby provides: a composite shaped body which exhibits excellent formability and fabricability and which is also suited for use, for example, in producing a silica glass provided with an electrical conductivity; and a silica glass (especially, an electrically conductive silica glass) obtained by firing the composite shaped body.

A process for manufacturing glass articles from powder at low temperatures includes the steps of preparing a slurry of powder suspended in a liquid; depositing the slurry on a substrate; drying the slurry to form a layer on the substrate; depositing slurry on the layer; drying the slurry deposited on the layer on the substrate to form another layer; repeating the steps of depositing a slurry and drying the to form a plurality of sequential layers on the substrate; and consolidating the plurality of sequential layers to form a glass article. The process requires a small manufacturing footprint, and facilitates the manufacture of very large near-net shape glass articles.

A quartz glass provides an opaque quartz glass having high light-shielding property, excellent mechanical strength and excellent cleaning resistance against hydrofluoric acid. By setting the maximum width of the amorphous bubbles existing in the opaque quartz glass to an average of 3 to 15 ?m and the density to 2.15 g/cm.sup.3 or more, the mechanical strength after baking and the cleaning resistance by hydrofluoric acid are improved. The opaque quartz glass has a whiteness at a thickness of 10 mm of 75 to 90%, the reflectance of light with a wavelength of 0.24 to 2.6 ?m at a thickness of 4 mm is 60 to 85%, and the bending strength after baking is 95 MPa. In addition, a foaming agent may be mixed in the opaque quartz glass. An opaque quartz glass having cleaning resistance against acid can be obtained.