One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, wherein the silicon dioxide granulate was made from pyrogenic silicon dioxide powder and the silicon dioxide granulate has a BET surface area in a range from 20 to 40 m.sup.2/g, making a glass melt out of silicon dioxide granulate in an oven and making a quartz glass body out of at least part of the glass melt. The oven has at least a first and a further chamber connected to one another via a passage. The temperature in the first chamber is lower than the temperature in the further chambers. On aspect relates to a quartz glass body which is obtainable by this process. One aspect relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Provided is a novel glass filler having a low permittivity. The glass filler provided includes a glass composition, wherein the glass composition includes, in wt %:95≤SiO.sub.2≤99.5; 0≤B.sub.2O.sub.3≤2; 0.01≤Al.sub.2O.sub.3≤4; 0≤R.sub.2O≤4; 0.01≤RO ≤4; and 0≤TiO.sub.2≤4, where RO is at least one selected from MgO, CaO, SrO, and ZnO, and R.sub.2O is at least one selected from Li.sub.2O, Na.sub.2O, and K.sub.2O. This glass filler can have a permittivity of less than 4 at 1 GHz.

A glass of the present invention includes as a glass composition, in terms of mass %, 50% to 75% of SiO.sub.2, 1% to 30% of Al.sub.2O.sub.3, 0% to 25% of B.sub.2O.sub.3, 0% to 10% of Li.sub.2O, 0.01% to 20% of Na.sub.2O, 0% to 10% of K.sub.2O, 0.0001% to 0.1% of Fe.sub.2O.sub.3, 0.00001% to 0.01% of Cr, 0.00001% to 0.01% of Ni, and 0.0001% to 0.5% of TiO.sub.2.

The present invention provides an alkali-free glass sheet, including as a glass composition, in terms of mol%, 64% to 71% of SiO.sub.2, 12.5% to 17% of Al.sub.2O.sub.3, 0% to 4% of B.sub.2O.sub.3, 0% to 0.5% of Li.sub.2O+Na.sub.2O+K.sub.2O, 6% to 11% of MgO, 3% to 11% of CaO, 0% to 6% of SrO, 0% to 1% of BaO, and 14% to 19% of MgO+CaO+SrO+BaO, and having a mole percent ratio (Al.sub.2O.sub.3/CaO)×{B.sub.2O.sub.3/(MgO+CaO+SrO+BaO)} of from 0 to 0.5, a mole percent ratio MgO/(CaO+SrO) of from 0.5 to 1.5, a mole percent ratio (MgO+CaO+SrO+BaO-Al.sub.2O.sub.3)×B.sub.2O.sub.3 of from 1 to 10, and a mole percent ratio SiO.sub.2×CaO/MgO of from 30 to 90.

Devised is a UV transmitting glass having a high transmittance in a deep UV region, and also having high weather resistance. The UV transmitting glass of the present invention is characterized by including as a glass composition, in terms of mass %, 55% to 80% of SiO.sub.2, 1% to 25% of Al.sub.2O.sub.3, 10.8% to 30% of B.sub.2O.sub.3, 0% to 10% of Na.sub.2O, 0% to less than 1.6% of K.sub.2O, 0.1% to 10% of Li.sub.2O+Na.sub.2O+K.sub.2O, 0% to 5% of BaO, and 0% to 1% of Cl, and having an external transmittance at a thickness of 0.5 mm and a wavelength of 200 nm of 38% or more.

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.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing silicon dioxide particles, making a glass melt out of the silicon dioxide particles in an oven and making a quartz glass body out of at least part of the glass melt. The oven has a gas outlet through which gas is removed from the oven, wherein the dew point of the gas on exiting the oven through the gas outlet is less than 0° C. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

One aspect relates to a process for the preparation of a quartz glass body including, providing a silicon dioxide granulate obtainable from a silicon dioxide powder, wherein the silicon dioxide granulate has a larger particle size than the silicon dioxide powder, making a 5 glass melt out of silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. The melting crucible has at least one inlet and at least one outlet. A least part of the glass melt is removed via the melting crucible outlet. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing 10 of the quartz glass body.

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.

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.