Abstract: The present invention relates to polymerizable compositions comprising at least one monomer and at least one modified metal oxide comprising the reaction product of a metal oxide and at least one coupling agent. In addition, polymer compositions comprising a polymer and the modified metal oxide are also disclosed. Finally, methods for preparing the polymerizable compositions and polymer compositions are described as are optical devices comprising the polymer compositions.

Abstract: The invention provides a substantially transparent material comprising particles of an inorganic titanate or an inorganic zirconate and at least one compound, wherein the particles are uniformly dispersed in the at least one compound, and wherein the particles are bonded to the at least one compound via at least one surface functional group of the particles. The invention also provides a light emitting device comprising a light emitting diode encapsulated with the substantially transparent material.

Abstract: The invention provides a substantially transparent material comprising particles of an inorganic titanate or an inorganic zirconate and at least one compound, wherein the particles are uniformly dispersed in the at least one compound, and wherein the particles are bonded to the at least one compound via at least one surface functional group of the particles. The invention also provides a light emitting device comprising a light emitting diode encapsulated with the substantially transparent material.

Abstract: The invention provides a composite material comprising (a) a polymer precursor or polymer having a refractive index and (b) particles comprising (1) cores based on at least two metal oxides, wherein the cores comprise aggregates of primary particles, and (2) a surface-treating agent bonded to the cores. The difference between the refractive index of the polymer precursor or polymer and the refractive index of the particles is about 2% or less of the refractive index of the polymer precursor or polymer. The invention further provides processes for preparing such a composite material.

Abstract: Silica sol techniques are described for making thick silica or silica based films useful for planar optical waveguides. The process involves coating of a colloidal silica sol onto a substrate, drying the sol, and consolidating the dried sol to form the planar waveguide. Coating is performed in a simple operation, either by dipping, or preferably by spin coating. In a preferred embodiment the substrate is coated with a wetting agent prior to spin coating. It is found that the wetting agent substantially improves the thickness uniformity of the layer. Thick waveguide layers may be produced by repeating the coating process one or more times to produce a layer with the desired thickness. Buried waveguides are produced by forming a doped core layer, patterning the doped core layer and using the coating technique of the invention to form the cladding material.

Abstract: The use of large dense vitreous spherical (LDVS) silica powders for making sol-gel silica bodies has been found to have important advantages. Among these are higher gel strength, higher silica loading, more rapid aging and drying of the gel, a reduction in the amount of organic additives leading to reduced process time required for organic burn-off, and easier removal of contaminant particles due to their larger size. It was also discovered that combining LDVS particles with conventional non-spherical, lower density, aggregate particle mixtures, further improves the process.

Abstract: Silica sol techniques are described for making thick silica or silica based films useful for planar optical waveguides. The process involves coating of a colloidal silica sol onto a substrate, drying the sol, and consolidating the dried sol to form the planar waveguide. Coating is performed in a simple operation, either by dipping, or preferably by spin coating. In a preferred embodiment the substrate is coated with a wetting agent prior to spin coating. It is found that the wetting agent substantially improves the thickness uniformity of the layer.

Abstract: The use of large dense vitreous spherical (LDVS) silica powders for making sol-gel silica bodies has been found to have important advantages. Among these are higher gel strength, higher silica loading, more rapid aging and drying of the gel, a reduction in the amount of organic additives leading to reduced process time required for organic burn-off, and easier removal of contaminant particles due to their larger size. It was also discovered that combining LDVS particles with conventional non-spherical, lower density, aggregate particle mixtures, further improves the process.

Abstract: The use of silica powders having large particle sizes in making sol-gel silica bodies has been found to have important advantages. Among these are higher gel strength, higher silica loading, more rapid aging and drying of the gel, a reduction in the amount of organic additives leading to reduced process time required for organic burn-off, and easier removal of contaminant particles due to their larger size. It was also discovered that spherical particle morphology contributes to the improved properties.

Abstract: The use of silica powders having large particle sizes in making sol-gel silica bodies has been found to have important advantages. Among these are higher gel strength, higher silica loading, more rapid aging and drying of the gel, a reduction in the amount of organic additives leading to reduced process time required for organic burn-off, and easier removal of contaminant particles due to their larger size. It was also discovered that spherical particle morphology contributes to the improved properties.

Abstract: A silica sol-gel fabrication process is provided which allows improved control of the shrinkage that takes place during the drying of a gel body. In particular, the invention makes it possible to attain extremely low shrinkage through the completion of the drying stage, e.g., below 1% linear shrinkage, in relatively large sol-gel bodies of (dry weight) 1 kg or more, typically 10 kg or more, or even 40 kg or more, compared to the much higher shrinkages typically encountered. Specifically, use of a particular polymeric additive makes it possible for a gel body to experience linear shrinkage at least 55% less than an identical process without the polymeric additive.

Abstract: A sol-gel process for fabricating bulk, germanium-doped silica bodies useful for a variety of applications, including core rods, substrate tubes, immediate overcladding, pumped fiber lasers, and planar waveguides, is provided. The process involves the steps of providing a dispersion of silica particles in an aqueous quaternary ammonium germanate solution—typically tetramethylammonium germanate, gelling the dispersion to provide a gel body, and drying, heat treating, and sintering the body to provide the germanium-doped silica glass.

Abstract: A silica sol-gel fabrication process is provided which allows improved control of the shrinkage that takes place during the drying of a gel body. In particular, the invention makes it possible to attain extremely low shrinkage through the completion of the drying stage, e.g., below 1% linear shrinkage, in relatively large sol-gel bodies of (dry weight) 1 kg or more, typically 10 kg or more, or even 40 kg or more, compared to the much higher shrinkages typically encountered. Specifically, use of a particular polymeric additive makes it possible for a gel body to experience linear shrinkage at least 55% less than an identical process without the polymeric additive.

Abstract: Silica sols exhibiting desirable yield-dilatancy are fabricated. A mixture comprising silica, water, and a pH-adjusting agent is provided, and the mixture is shear-mixed. The desirable properties of the resultant sol are attained by using a concentration of pH-adjusting agent that provides a viscosity within a particular range during shear mixing. The requisite pH range, however, changes depending on the properties of the silica mixture. A discovered technique for determining this changing pH range is by selecting the pH based on the silica surface area per unit volume of the mixture.

Abstract: The invention reflects discovery of a liquid phase doping technique that, unlike previous techniques, exhibits very little fluorine depletion upon subsequent heating. The invention involves the steps of providing a silica sol comprising a tetraalkylammonium hydroxide and a di-, tri-, or tetraalkylammonium fluoride, the sol having pH of about 10 to about 14, adding a gelling agent to the sol to induce gelation, casting or extruding the sol to form a gel body, and then drying, heat treating, and sintering the body. Advantageously, the fluorine-containing compound is tetramethylammonium fluoride.