Abstract:
A known quartz glass crucible for crystal pulling consists of a crucible wall, having an outer layer which is provided in an external area thereof with a crystallisation promoter which results in crystallisation of quartz glass, forming cristobalite when the quartz glass crucible is heated according to specified use in crystal pulling. The aim of the invention is to provide a quartz glass crucible which has a long service life. As a result, the crystallisation promoter contains, in addition to a silicon, a first component which acts as a reticulating agent in quartz glass and a second component which is free of alkali metals and which acts as an agent forming separating points in quartz glass. The above mentioned components are contained and incorporated into a doping area (8) of the outer layer (6) having a layer thickness of more than 0.2 mm.
Abstract:
A photosensitive glass made of a ternary compound SiO2:SnO2:R2O where R is a Group I element such as Na, K or Li. The addition of an oxide of a Group I element increases the solubility of tin oxide in a silica matrix and produces a glass which is highly photosensitive and in which optically written refractive index modulations have remarkable temperature stability (solid circles) at least as good as that of the binary glass SiO2:SnO2 (open circles) and much superior to that of conventional germanosilicate glass (solid triangles) or borogermanosilicate glass (open triangles). The inclusion of the Group I oxide effectively increases the solubility of tin oxide in the non-crystalline silica matrix well above the 1% limit of SiO2:SnO2 photosensitive glass, at which Sn would normally crystallize in the oxide. By contrast to boron or phosphorous co-dopants, the introduction of the Group I element does not appear to cause any increase in the background refractive index, allowing the manufacture of waveguide devices compatible with standard telecommunication fibers.
Abstract:
The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.
Abstract:
The invention relates to a glass excellent in infrared absorption capability and corrosion resistance, and its fabrication process. A compound of divalent copper and a compound of a metal species for a network modifier oxide are introduced in a wet gel. Then, the wet gel is dipped in a dipping solution having a low solubility with respect to the compound of divalent copper and the compound of a metal species for a network modifier oxide for the precipitation in the wet gel of the divalent-t copper compound and the compound of a metal species for a network modifier oxide, followed by drying and firing. Thus, an infrared absorbing glass comprising 70 to 98 mol % of SiO2, 1 to 12 mol % of CuO and 1 to 18 mol % of a network modifier oxide other than CuO is fabricated.
Abstract:
A method for controlling the refractive index achieved using a fluorine dopant gas, wherein CF4 is employed as the dopant gas, and the soot preform is doped using the CF4 for a time and temperature sufficient to result in a decrease in fluorine dopant nearest the surface which is in contact with the CF4 gas.
Abstract:
Optical quality glass having a selected refractive index is produced by a two stage drying process. A gel is produced using sol-gel chemistry techniques and first dried by controlled evaporation until the gel volume reaches a pre-selected value. This pre-selected volume determines the density and refractive index of the finally dried gel. The gel is refilled with solvent in a saturated vapor environment, and then dried again by supercritical extraction of the solvent to form a glass. The glass has a refractive index less than the full density of glass, and the range of achievable refractive indices depends on the composition of the glass. Glasses having different refractive indices chosen from an uninterrupted range of values can be produced from a single precursor solution.
Abstract:
A metal halide or mercury lamp including an arc tube comprised of a glass composition consisting essentially of at least 90 weight percent SiO.sub.2 and including between about 10 and 1000 parts per million of a trivalent element slected from the group consisting of Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Unq, Unp, Ga, and mixtures thereof such that the viscosity of the glass composition is greater than 10.sup.14.5 poise at 1100.degree. C.
Abstract:
A glass composition, particularly well suited for use in constructing sodium containing lamp envelopes. The glass composition is comprised of silica doped with yttrium and/or cesium, preferably in combination aluminum.
Abstract:
A chemically durable porous glass of which the skeleton mainly comprises SiO.sub.2 -ZrO.sub.2 system glass having a ZrO.sub.2 content of 2 or more wt %, and a process for the production of such glass.
Abstract:
Quartz glass includes iron and aluminum. The total iron content ranges from 0.01 to 5% by weight, and the total aluminum content ranges from 0.01 to 10% by weight. The quartz glass exhibits infrared rays-absorbing ability and visible light-transmitting ability. Also a process for making such a quartz glass is disclosed.