Abstract: The invention relates to a borosilicate glass of high chemical resistance and low viscosity which contains zirconium oxide and lithium oxide. The borosilicate glass has hydrolytic resistance (in accordance with DIN ISO 719), class 1 acid resistance (in accordance with DIN 12116), and class 1 alkali resistance (in accordance with DIN ISO 659), and with a low operating temperature V.sub.A of between 1180.degree. C. to 1230.degree. C. and a coefficient of thermal expansion .alpha..sub.20/300 of 4.9.times.10.sup.-6 K.sup.-1. The borosilicate glass has the composition (in % by weight, based on oxide): SiO.sub.2 73-75; B.sub.2 0.sub.3 7-10; Al.sub.2 0.sub.3 5-7; ZrO.sub.2 1-3; Li.sub.2 0 0.5-1.5; Na.sub.2 0 0-10; K.sub.2 0 0-10; MgO 0-3; CaO 0-3; BaO 0-3; SrO 0-3; ZnO 0-3; ratio of SiO.sub.2 /B.sub.2 0.sub.3 .gtoreq.7.5; .SIGMA. SiO.sub.2 +Al.sub.2 0.sub.3 +ZrO.sub.2 80-83 and .SIGMA. MgO+CaO+BaO+SrO+ZnO.ltoreq.3, and fluorides 0-3.

Abstract: The invention relates to brownish, brown to black colored borosilicate glasses which have stepped grades of transmission in the NIR range or are fully non-transmitting. The borosilicate glass, primarily the borosilicate glass 3.3, is melted with defined additives of titanium carbide and/or metallic silicon. The glasses produced in accordance with the invention are to be used as filters, glass vessels and/or decorative colored glass in construction and for decorating because of their absorption/transmission characteristics. On the other hand, the glasses produced in accordance with the invention can also be used as absorbers in solar technology when the light transmissibility in the NIR/IR range is sufficiently low.

Abstract: The invention relates to gray, bluish, blue to black colored borosilicate glasses which have a stepped transmission grade in the near infrared range or are fully non-transmitting. The borosilicate glass with defined additions of titanium dioxide is melted together with a reduction agent such as Si(metallic). The glasses produced in accordance with the invention are used as filters because of their absorption/transmission characteristic or, if the light transmissibility in the near infrared/infrared ranges is sufficiently low, the glasses can also be used as absorbers in solar technology, as a glass used in areas of the home and/or as decorative colored glass in construction and for decorating.

Abstract: Reducing melt borosilicate glass having a UV transmittance of at least 85% for ultraviolet radiation having a wavelength of 254 nm for a sample thickness of 1 mm and a water-resistance of less than 100 micrograms, advantageously less than 62 micrograms, Na.sub.2 O per gram of glass powder according to ISO 719 and a thermal expansion coefficient .alpha..sub.20/300 of from 5 to 6.times.10.sup.-6 K.sup.-1 and comprising from 58 to 65% by weight SiO.sub.2, from 18 to 20.5% by weight B.sub.2 O.sub.3, from 8.1 to 10.4% by weight Al.sub.2O.sub.3, from 0 to 1% by weight CaO, from 0 to 2% by weight BaO, from 0 to 2% by weight SrO, from 0 to 1.5% by weight Li.sub.2 O, from 5.5 to 8.5% by weight Na.sub.2 O, from 0 to 3% by weight K.sub.2 O and from 0 to 2% by weight fluorine. The sum total content of all of the alkali metal oxides present in the glass is not greater than 10% and the sum total content of the CaO, BaO and SrO is not greater than 3% and the molar ratio of Al.sub.2 O.sub.3 : Na.sub.2 O is from 0.6 to 1.

Abstract: Borosilicate glass weak in boric acid having a high chemical stability with an alkali resistance according to DIN 52 322 of LBK-Class 1, a thermal expansion .alpha..sub.20/300 between 4.0 to 5.3.times.10.sup.-6 K.sup.-1, a ratio .alpha.'/.alpha. of thermal expansion coefficients above T.sub.g (.alpha.') to below T.sub.g (.alpha.) of 4 to 8, a glass transformation temperature between 500.degree. C. and 600.degree. C., high radiation transmittance and a UV transmission .tau..sub.250 nm/1 mm of 0 to 70% or .tau..sub.300 nm/1 mm of 0 to 91% of the composition in percent by weight on oxide basis of: SiO.sub.2 >75; B.sub.2 O.sub.3 1 to <9; Al.sub.2 O.sub.3 3 to 6; Li.sub.2 O 0 to 4; Na.sub.2 O 0 to 8; K.sub.2 O 0 to 6; MgO 0 to 3; CaO 0 to 3; BaO 0 to 2; SrO 0 to 2; ZnO 0 to 3; ZrO.sub.2 0 to 3; SnO.sub.2 0 to 3; SnO 0 to 3; TiO.sub.2 0 to 2; CeO.sub.2 0 to 2; Fe.sub.2 O.sub.3 0 to 1; with SiO.sub.2 +B.sub.2 O.sub.3 >83; SiO.sub.2 :B.sub.2 O.sub.3 >8; SiO.sub.2 +Al.sub.2 O.sub.3 +ZrO.sub.2 >83; Li.

Abstract: The borosilicate glass has a UV transmission of at least 80% at a UV wavelength of about 254 nm for a borosilicate glass sheet thickness of 2 mm, a linear coefficient of thermal expansion, .alpha..sub.20/300, of 3.2 to 3.4.times.10.sup.-6 K.sup.-1, a hydrolytic resistance of class 1 and a composition in % by weight based on oxide of______________________________________ glass formers <96%, SiO.sub.2 from 79.0 to 81.0%, B.sub.2 O.sub.3 from 12.5 to 13.0%, Al.sub.2 O.sub.3 from 2.0 to 4.0%, alkali metal oxides >2%, ______________________________________wherein said alkali metal oxides include from 2.0 to 3.5% said K.sub.2 O and from 1.0 to 2.0% said Li.sub.2 O, ______________________________________ alkaline earth metal <0.3%, oxides + ZnO reducing agent 0.025 to 2%, and non-oxidizing fining agent 0 to 3%. ______________________________________The weight ratio of K.sub.2 O to Li.sub.2 O is from 2:1 to 1:1 in the borosilicate glass.