Abstract:
An object of the invention is a method for at least partially treating biologically active sols, gels, mixtures or composites of sols and gels, and/or sol-gel derived materials, said sols, gels, mixtures or composites of sols and gels, and/or sol-gel derived materials comprising OH-groups and being at least partially amorphous, the said treatment being performed with a localised electromagnetic and/or acoustic energy. Other objects of the invention are a method for coating a device with biologically active sols, gels, mixtures or composites of sols and gels, and/or sol-gel derived materials and a method for modifying the biological activity of biologically active sols, gels, mixtures or composites of sols and gels, and/or sol-gel derived materials. All these methods use treatment with localised electromagnetic and/or acoustic energy. The invention also relates to the use of said method for the fabrication of different devices and to the attachment of at least two devices.
Abstract:
These glass bodies are light weight porous structures such as a boules of high purity fused silica or ultra-low expansion glass. More specifically, the porous structures are supports for mirror blanks. Porous glass is made utilizing flame deposition of pure silica or doped silica in a manner similar to the production of high purity fused silica. Bubbles or seeds are formed in the glass during laydown. Several means of creating and controlling these seeds are available. The processes use incomplete combustion to create the bubbles. There are a number of different steps to create the incomplete combustion. One such step involves maintaining a short distance between the hydrolysis flame and the glass precursor.
Abstract:
These glass bodies are light weight porous structures such as a boules of high purity fused silica or ultra-low expansion glass. More specifically, the porous structures are supports for mirror blanks. Porous glass is made utilizing flame deposition of pure silica or doped silica in a manner similar to the production of high purity fused silica. Bubbles or seeds are formed in the glass during laydown. Several means of creating and controlling these seeds are available. The processes use incomplete combustion to create the bubbles. There are a number of different steps to create the incomplete combustion. One such step involves maintaining a short distance between the hydrolysis flame and the glass precursor.
Abstract:
Ultra-low expansion silica-titania glasses are produced by flame deposition of a mixture of vaporized octamethylcyclotetrasiloxane (OMCTS) and vaporized titanium isopropoxide (Ti-Ipox). Ti-Ipox is vaporized by nitrogen bubbled from conduit (16) into tank (12) and OMCTS is vaporized by nitrogen bubbled from conduit (14) in tank (10). Before being mixed with the Ti-Ipox, the OMCTS is dried so that its water content is less than 2 ppm and preferably less than 1 ppm. In this way, the formation of a precipitate on the glass making equipment (e.g., burners (28), distribution manifold (26), static mixer (18), joint (13), and conduits (20, 22, 24 and 30)) is avoided. Such a precipitate if allowed to form will result in premature shutdown of the glass making process and can result in undesirable variations in the composition of the silica-titania glass being produced.
Abstract:
The invention concerns a method for making an optical fibre (15) preform (3), consisting in forming at least one external silica-based layer (23) by depositing silica on a primary preform (24), consisting of a bar comprising mainly silica and comprising an external peripheral silica-based part (22). The invention is characterised in that it consists in adjusting the external deposit layer (23) viscosity so that it is substantially identical to the primary preform (24) external peripheral part (22) viscosity by adding to the silica, for a substantial part of the external deposit (23), at least a doping agent selected in the group formed by the following compounds: CaF2, MgF2, AlF2, B2O and Al2O3.
Abstract:
The present invention is directed to a process for forming a preform suitable for consolidation to a glass blank for producing an optical waveguide fiber. The preform comprises a core portion and an inner cladding layer surrounding the core portion and contains SiO2 and TiO2. A portion of the TiO2 in the preform is in a crystalline form that is predominantly rutile. In addition to SiO2 and TiO2, the preform contains an additive compound that is preferentially sacrificed instead of TiO2 when the preform is consolidated. The process includes oxidizing Si and Ti containing compounds as well as a precursor of the additive compound to form SiO2, TiO2, and the additive compound. The preform containing these materials is then formed. In addition, the preform can be converted to a glass blank by consolidation of the preform.
Abstract:
A method for producing an optical fibre which has been treated with titanium dioxide to improve its corrosion resistance includes stretching an assembly consisting of an outer sleeve having engaged therein a bar which is partially or entirely made of synthetic silica. When treating said fibre, the outside of the coupling sleeve is coated, prior to assembling the components, with a deposit of vitrified synthetic silica containing titanium dioxide.
Abstract:
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/K2 at 20⃘C. The second dopant can be optional. The composition of the glass article may also contain an OH concentration of less than 100 ppm.
Abstract:
A method of forming a doped silica-titania glass is provided. The method includes blending batch materials comprising silica, titania, and at least one dopant. The method also includes heating the batch materials to form a glass melt. The method further includes consolidating the glass melt to form a glass article, and annealing the glass article.
Abstract:
Ultralow expansion titania-silica glass. The glass has high hydroxyl content and optionally include one or more dopants. Representative optional dopants include boron, alkali elements, alkaline earth elements or metals such as Nb, Ta, Al, Mn, Sn Cu and Sn. The glass is prepared by a process that includes steam consolidation to increase the hydroxyl content. The high hydroxyl content or combination of dopant(s) and high hydroxyl content lowers the fictive temperature of the glass to provide a glass having a very low coefficient of thermal expansion (CTE), low fictive temperature (T f ), and low expansivity slope.