To provide a a glass composition which can be used for a dental porcelain or a dental ceramics coloring material, and has low temperature meltability, acid resistance and preservation stability under the humid environment which are required for a dental porcelain or a dental ceramics coloring material, and a dental porcelain and dental ceramics coloring material which contain the glass composition of the present disclosure. To provide a low melting glass composition with softening point (Ts) less than 600 C. comprising as a component; SiO.sub.2: 55.0 to 75.0 wt. %, B.sub.2O.sub.3: 6.1 to 12.0 wt. %, Al.sub.2O.sub.3: 2.0 to 8.0 wt. %, ZnO: 2.0 to 8.5 wt. % and two or more kinds of alkali metal oxide: 10.5 to 20.0 wt. %.

A glass composition includes: 50 mol % to 69 mol % SiO.sub.2; 12.5 mol % to 25 mol % Al.sub.2O.sub.3; 0 mol % to 8 mol % B.sub.2O.sub.3; greater than 0 mol % to 4 mol % CaO; greater than 0 mol % to 17.5 mol % MgO; 0.5 mol % to 8 mol % Na.sub.2O; 0 mol % to 2.5 mol % La.sub.2O.sub.3; and greater than 8 mol % to 18 mol % Li.sub.2O, wherein (Li.sub.2O+Na.sub.2O+MgO)/Al.sub.2O.sub.3 is from 0.9 to less than 1.3; and Al.sub.2O.sub.3+MgO+Li.sub.2O+ZrO.sub.2+La.sub.2O.sub.3+Y.sub.2O.sub.3 is from greater than 23 mol % to less than 50 mol %. The glass composition may be characterized by at least one of the following: a K.sub.1C value measured by a chevron short bar method of at least 0.75; and a K.sub.1C value measured by a double torsion method of at least 0.8. The glass composition is chemically strengthenable. The glass composition may be used in a glass article or a consumer electronic product.

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.

The present invention relates to a moldable nanocomposite for producing a transparent article made of multicomponent fused silica glass, the moldable nanocomposite comprising: an organic binder; and a fused silica glass powder dispersed in the organic binder, the fused silica glass powder comprising fused silica glass particles having a diameter in the range from 5 nm to 500 nm, wherein the fused silica glass powder is pre-modified with a dopant and/or wherein at least one non-crystalline modifying agent is contained in the moldable nanocomposite and one or more dopant reagents selected from organoelement compounds, metal complexes and salts are contained in the moldable nanocomposite as the at least one non-crystalline modifying agent, and wherein the content of the fused silica glass powder in the moldable nanocomposite is at least 5 parts per volume based on 100 parts per volume of the organic binder. Further, the present invention relates to a method of producing a transparent article made of multicomponent fused silica glass.

The present invention provides a glass fiber composition, glass fiber and composite material therefrom. The glass fiber composition comprises the following components expressed as percentage by weight: 58-63% SiO.sub.2, 13-17% Al.sub.2O.sub.3, 6-11.8% CaO, 7-11% MgO, 3.05-8% SrO, 0.1-2% Na.sub.2O+K.sub.2O+Li.sub.2O, 0.1-1% Fe.sub.2O.sub.3, 0-1% CeO.sub.2 and 0-2% TiO.sub.2, wherein a weight percentage ratio C1=(MgO+SrO)/CaO is greater than 1. Said composition greatly improves the refractive index of glass, significantly shields against harmful rays for humans and further reduces glass crystallization risk and production costs, thereby making it more suitable for large-scale production with refractory-lined furnaces.

A method for producing rare earth metal-doped quartz glass includes the steps of (a) providing a blank of the rare earth metal-doped quartz glass, and (b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis. Some rare earth metals, however, show a discoloration of the quartz glass, which hints at an unforeseeable and undesired change in the chemical composition or possibly at an inhomogeneous distribution of the dopants. To avoid this drawback and to provide a modified method which ensures the production of rare earth metal-doped quartz glass with reproducible properties, during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or a neutral plasma.

An article includes SiO.sub.2 from about 40 mol % to about 80 mol %, Al.sub.2O.sub.3 from about 1 mol % to about 20 mol %, B.sub.2O.sub.3 from about 3 mol % to about 50 mol %, WO.sub.3 plus MoO.sub.3 from about 1 mol % to about 18 mol % and at least one of: (i) Au from about 0.001 mol % to about 0.5 mol %, (ii) Ag from about 0.025 mol % to about 1.5 mol %, and (iii) Cu from about 0.03 mol % to about 1 mol %, and R.sub.2O from about 0 mol % to about 15 mol %. The R.sub.2O is one or more of Li.sub.2O, Na.sub.2O, K.sub.2O, Rb.sub.2O and Cs.sub.2O. R.sub.2O minus Al.sub.2O.sub.3 ranges from about 12 mol % to about 3.8 mol %.

A radiation-resistant laser optical fiber preform core rod at least includes one type of activated ion (Yb.sup.3+, Er.sup.3+) and one or more types of co-doped ion (Al.sup.3+, P.sup.5+, Ge.sup.4+, Ce.sup.3+, F.sup.?), and OD group of 16-118 ppm. Irradiation resistance of core rod glass can be effectively improved by sequentially performing pre-treatments, i.e. deuterium loading, pre-irradiation and thermal annealing on a preform core rod. Electron paramagnetic resonance test shows that, under the same radiation condition, the radiation induced color center concentration in a preform core rod treated by the method above is lower than in an untreated core rod by one or more orders of magnitude. The obtained core rod can be used for preparing a radiation-resistant rare earth-doped silica fiber, and has the advantages of high laser slope efficiency, low background loss, being able to be used stably in a vacuum environment for a long time, for example.

One aspect is an oven including a melting crucible with a crucible wall, a solids feed with an outlet, a gas inlet and a gas outlet, wherein in the melting crucible the gas inlet is arranged below the solids feed outlet and the gas outlet is arranged at the same height as or above the solids feed outlet. One aspect further relates to a process for making a quartz glass body, including providing and introducing a bulk material selected from silicon dioxide granulate and quartz glass grain into the oven and providing a gas, making a glass melt from the bulk material, and making a quartz glass body from at least a part of the glass melt. One aspect relates to a quartz glass body obtainable by this process and a light guide, an illuminant and a formed body which are each obtainable by processing the quartz glass body further.

The invention relates to a process for the preparation of a quartz glass body comprising the process steps i.) Providing a silicon dioxide granulate, ii.) Making a glass melt from the silicon dioxide granulate in an oven, and iii.) Making a quartz glass body from at least a part of the glass melt, wherein the oven comprises a hanging sinter crucible. The invention also relates to a quartz glass body which is obtainable by this process. The invention further relates to a light guide, an illuminant and a formed body which are each obtainable by further processing the quartz glass body.