A glass substrate for a high-frequency device, which contains SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of alkaline earth metal oxides in the range of 0.1-13% in terms of mole percent on the basis of oxides, wherein at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

Provided is a glass composition for glass fiber having a low dielectric constant and a low dielectric loss tangent, suppressing occurrence of phase separation, and reducing viscosity at high temperatures. The glass composition for glass fiber includes: SiO.sub.2 in the range of 52.0 to 59.5% by mass; B.sub.2O.sub.3 in the range of 17.5 to 25.5% by mass; Al.sub.2O.sub.3 in the range of 9.0 to 14.0% by mass; SrO in the range of 0.5 to 6.0% by mass; MgO in the range of 1.0 to 5.0% by mass; and CaO in the range of 1.0 to 5.0% by mass, and includes F.sub.2 and Cl.sub.2 in the range of 0.1 to 2.5% by mass in total, with respect to the total amount.

Provided is a glass composition for glass fiber having a low dielectric constant and a low dielectric loss tangent, suppressing occurrence of phase separation, and reducing viscosity at high temperatures. The glass composition for glass fiber includes: SiO.sub.2 in the range of 52.0 to 59.5% by mass; B.sub.2O.sub.3 in the range of 17.5 to 25.5% by mass; Al.sub.2O.sub.3 in the range of 9.0 to 14.0% by mass; SrO in the range of 0.5 to 6.0% by mass; MgO in the range of 1.0 to 5.0% by mass; and CaO in the range of 1.0 to 5.0% by mass, and includes F.sub.2 and Cl.sub.2 in the range of 0.1 to 2.5% by mass in total, with respect to the total amount.

A chemically temperable borosilicate glass article has a low boron content and a corresponding Na.sub.2O content. The articles have good diffusivities and hydrolytical resistance values. When chemically tempered, the borosilicate glass article exhibits a compressive stress CS >400 MPa and a penetration depth DoL >20 μm. A pharmaceutical primary packaging including the borosilicate glass article is also disclosed.

An imaging system includes at least one laser light source having a wavelength in the visible spectral range and a beam guidance element with high solarization resistance at high beam power densities. The invention also relates to the use of the imaging system, in particularly in projectors and in material processing.

A formed or non-flat formed glass is provided that exhibits high transmittance to electromagnetic radiation in a range of wavelengths from 200 nm to 1500 nm. The transmittance for the formed or non-flat formed glass having a thickness of 1 mm is 20% or more at a wavelength of 254 nm, 82% or more at a wavelength of 300 nm, 90% or more at a wavelength of 350 nm, 92% or more at a wavelength of 546 nm, 92.5% or more at a wavelength of 1400 nm, 91.5% or more in a wavelength range from 380 nm to 780 nm, and 92.5% or more in a wavelength range from 780 nm to 1500 nm.

A formed or non-flat formed glass is provided that exhibits high transmittance to electromagnetic radiation in a range of wavelengths from 200 nm to 1500 nm. The transmittance for the formed or non-flat formed glass having a thickness of 1 mm is 20% or more at a wavelength of 254 nm, 82% or more at a wavelength of 300 nm, 90% or more at a wavelength of 350 nm, 92% or more at a wavelength of 546 nm, 92.5% or more at a wavelength of 1400 nm, 91.5% or more in a wavelength range from 380 nm to 780 nm, and 92.5% or more in a wavelength range from 780 nm to 1500 nm.

To provide a glass composition for glass fiber having a low dielectric loss tangent, suppressing the occurrence of phase separation, having a reduced viscosity at high temperatures, and reducing the occurrence of striae. The glass composition for glass fiber includes 52.0 to 57.5% by mass of SiO.sub.2, 19.5 to 25.5% by mass of B.sub.2O.sub.3, 8.0 to 13.0% by mass of Al.sub.2O.sub.3, 0 to 2.0% by mass of MgO, 0 to 6.0% by mass of CaO, 0.5 to 6.5% by mass of SrO, and 0.1 to 3.0% by mass of TiO.sub.2, the ratio of Al.sub.2O.sub.3 to B.sub.2O.sub.3 is 0.35 to 0.54, and the content SI of SiO.sub.2, the content B of B.sub.2O.sub.3, the content M of MgO, the content C of CaO, the content SR of SrO, and the content T of TiO.sub.2 satisfy the following formula (1): 6.90≤100×(B/SI).sup.2×{SR/(C+SR)}.sup.2/3×{T/(M+T)}.sup.1/2≤12.30 (1).

A UV transmitting glass of the present invention is characterized by including as a glass composition, in terms of mass %, 60% to 78% 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 less than 1.9% of Li.sub.2O, 0% to 8% of Na.sub.2O, 1.6% to 8% of K.sub.2O, 1.6% to 10% of Li.sub.2O+Na.sub.2O+K.sub.2O, 0% to less than 1.9% of BaO, 0% to less than 1.9% of Li.sub.2O+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 40% or more.

Alkali-doped boroaluminosilicate glasses are provided. The glasses include the network formers SiO.sub.2, B.sub.2O.sub.3, and Al.sub.2O.sub.3. The glass may, in some embodiments, have a Young's modulus of less than about 65 GPa and/or a coefficient of thermal expansion of less than about 40×10.sup.−7/° C. The glass may be used as a cover glass for electronic devices, a color filter substrate, a thin film transistor substrate, or an outer clad layer for a glass laminate.