Provided is a glass composition for glass fiber that suppresses variations in fiber diameter of glass fiber including 45.60 to 59.00% by mass of SiO.sub.2, 10.00 to 16.00% by mass of Al.sub.2O.sub.3, 17.00 to 25.00% by mass of CaO, 0.01 to 9.50% by mass of TiO.sub.2, 0.03 to 7.00% by mass of P.sub.2O.sub.5, 0.00 to 9.50% by mass of ZnO, 0.00 to 2.00% by mass of SO.sub.3, 0.01 to 11.50% by mass in total of ZnO and SO.sub.3, and 0.00 to 2.00% by mass in total of Na.sub.2O, K.sub.2O, and Li.sub.2O, with respect to the total amount. The content SI of SiO.sub.2, the content A of Al.sub.2O.sub.3, the content C of CaO, the content T of TiO.sub.2, the content P of P.sub.2O.sub.5, the content Z of ZnO, and the content SO of SO.sub.3 satisfy the following formula (1):
15.0(SI/C).sup.2(A/T){P/(SO+Z)}.sup.1/4690.1(1).

Embodiments of the present invention provides fiberizable glass compositions formed from batch compositions comprising amounts of one or more glassy minerals, including perlite and/or pumice.

A single-mode fiber with ultralow attenuation includes a core layer and cladding layers. The cladding layers includes an inner cladding layer surrounding the core layer, a trench cladding layer surrounding the inner cladding layer, an auxiliary outer cladding layer surrounding the trench cladding layer, and an outer cladding layer surrounding the auxiliary cladding layer. The core layer has a radius of 3.9-4.8 m and a relative refractive index difference of 0.08% to 0.10%. The inner cladding layer has a radius of 9-14 m and a relative refractive index difference of 0.40% to 0.15%. The trench cladding layer has a radius of 13-25 m and a refractive index difference of 0.7% to 0.3%. The auxiliary outer cladding layer has a radius of 30-50 m and a relative refractive index difference of 0.4% to 0.15%. The outer cladding layer is a pure silicon dioxide glass layer.

Described herein are systems, methods, and articles of manufacture for a coated fiber modified by actinic radiation to increase back-scattering, which experiences very little back-scattering decay at a temperature and time of exposure that is sufficient to noticeably degrade the coating and/or noticeably degrade the optical fiber due to outgassing of hydrogen from the coating. In one embodiment, an optical fiber comprises a fiber length, a coating having a treated coating weight, wherein the treated coating weight is at least 25% less of an original coating weight prior to an annealing treatment, and an optical back-scatter along the fiber length greater than a Rayleigh back-scattering over the fiber length, wherein the optical back-scatter does not decrease along the fiber length by more than 3 dB after exposure to annealing treatment. A further embodiment relates to a method comprising receiving an optical fiber at an inlet of at least one heat source, the optical fiber including a coating having an original coating weight and an optical back-scatter along a fiber length and applying an annealing treatment to the optical fiber by the least one heat source at a predetermined temperature T.sub.a during a predetermined time t.sub.a, wherein the original coating weight is reduced by at least 25% to a treated coating weight during the annealing treatment, wherein the optical back-scatter does not decrease along the fiber length by more than 3 dB after the annealing treatment.

An object of the present invention is to provide an evaluation method and an evaluation device for easily determining whether or not a structural parameter of a multi-core fiber satisfies a desired connection loss value (a specification). The evaluation method according to the present invention includes a step of measuring center coordinates of each core with the center coordinates when a clad is approximated by a circle as an origin in an observed cross-sectional structure of the multi-core fiber to be objected, obtaining a length of a line segment connecting the origin and the center of each core and an angle formed by two line segments connecting the origin and two adjacent cores, and judging whether or not a desired connection loss characteristic is satisfied on the basis of whether or not the values satisfy a predetermined determination formula.

The present invention relates to a method of providing thermal and/or acoustic insulation to a structure, comprising the steps of: providing a substrate which comprises fibres; applying the substrate to the structure; blending the substrate with a binder composition before, during or after application of the substrate to the structure; allowing curing of the binder composition after the substrate and the binder composition have been applied to the structure; wherein the binder composition comprises at least one hydrocolloid. The present invention also relates to an insulated structure obtainable by said method.

An electronic-grade glass fiber composition includes the following components with corresponding amounts by weight percentages 51.0-57.5% SiO.sub.2, 11.0-17.0% Al.sub.2O.sub.3, >4.5% and 6.4% B.sub.2O.sub.3, 19.5-24.8% CaO, 0.1-1.9% MgO, 0.05-1.2% R.sub.2O=Na.sub.2O+K.sub.2O+Li.sub.2O, 0.05-0.8% Fe.sub.2O.sub.3, 0.01-1.0% TiO.sub.2, and 0.01-1.0% F.sub.2. A weight percentage ratio C1=SiO.sub.2/B.sub.2O.sub.3 is 8.1-12.7, a weight percentage ratio C2=B.sub.2O.sub.3/(R.sub.2O+MgO) is 1.7-6.3, and a total weight percentage of the above components is greater than or equal to 99%.

An optical fiber having a core comprising silica and greater than 1.5 wt % chlorine and less than 0.5 wt % F, said core having a refractive index .sub.1MAX, and an inner cladding region having refractive index .sub.2MIN surrounding the core, where .sub.1MAX>.sub.2MIN.

In one aspect, a method of making a gypsum panel includes depositing an aqueous liquid containing a wetting agent onto a fiberglass mat, such that the aqueous liquid penetrates an entire thickness of the fiberglass mat, and depositing a gypsum slurry onto the fiberglass mat onto which the aqueous liquid has been deposited, such that the gypsum slurry penetrates at least a portion of the fiberglass mat. In another aspect, a method of making a gypsum panel includes depositing an aqueous liquid containing a wetting agent onto a fiberglass mat, and depositing a gypsum slurry onto the fiberglass mat onto which the aqueous liquid has been deposited, prior to drying of the aqueous liquid, such that the gypsum slurry penetrates at least a portion of the fiberglass mat.

New glass compositions and applications thereof are disclosed. A glass composition as described herein can include 50 to 55 weight percent SiO.sub.2, 17 to 26 weight percent B.sub.2O.sub.3, 13 to 19 weight percent Al.sub.2O.sub.3, 0 to 8.5 weight percent MgO, 0 to 7.5 weight percent ZnO, 0 to 6 weight percent CaO, 0 to 1.5 weight percent Li.sub.2O, 0 to 1.5 weight percent F.sub.2, 0 to 1 weight percent Na.sub.2O, 0 to 1 weight percent Fe.sub.2O.sub.3, 0 to 1 weight percent TiO.sub.2, and 0 to 8 weight percent of other constituents. Also described herein are glass fibers formed from such compositions, composites, and articles of manufacture comprising the glass compositions and/or glass fibers.