Glass-based articles comprise stress profiles providing improved drop performance. A glass-based substrate comprises: a glass transition temperature (T.sub.g), a liquid fragility index (m), and fictive temperature (T.sub.f), wherein T.sub.g is less than or equal to 650 C., a value of T.sub.f minus T.sub.g is greater than or equal to 30 C., and m is greater than or equal to 25. A stress relaxation rate is greater than or equal to 10%, or 20% or more. The articles can comprise a lithium-based aluminosilicate composition and a fracture toughness that is greater than or equal to 0.75 MPa*m.sup.0.5. The stress profiles comprise: a spike region extending from the first surface to a knee; and a tail region extending from the knee to a center of the glass-based article, the tail region comprising: a negative curvature region wherein a second derivative of stress as a function of depth is negative; a depth of compression (DOC) that is greater than or equal to 0.22t, and a parabolic region originating at the DOC and extending to the center of the glass-based article.

A vehicular laminated glass for separating a vehicle interior from an external environment is presented. The laminated glass includes inner and outer panes made of glass and having respective thicknesses of less than or equal to 0.4 mm, and greater than or equal to 1.5 mm, and an acoustically damping intermediate layer that bonds the inner pane to the outer pane. According to one aspect, the acoustically damping intermediate layer has two outer polymeric layers between which an inner polymeric layer is positioned, the outer polymeric layers having lower elasticity or plasticity than the inner polymeric layer. According to another aspect, the inner polymeric layer has a thickness of 0.05 mm to 0.40 mm, each of the outer polymeric layers have a thickness of 0.20 mm to 0.60 mm, and the total thickness of the acoustically damping intermediate layer is at least 0.70 mm.

A doping optimized single-mode optical fiber with ultra low attenuation includes a core layer and cladding layers. The cladding layers has 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 outer cladding layer. The content of fluorine in the core layer is 0.5 wt %, Ge0.12%, n.sub.10.12%. The content of fluorine in the inner cladding layer is 0.5-1.5 wt %, n.sub.20.14%. The content of fluorine in the trench cladding layer is 1-3 wt %, n.sub.30.25%. The content of fluorine in the auxiliary outer cladding layer is 0.5-2 wt %, n.sub.40.14%. The outer cladding layer is a pure silicon dioxide glass layer and/or a metal-doped silicon dioxide glass layer.

There is provided a method for producing a low-loss alkali metal-doped silica core optical fiber having excellent hydrogen resistance. The method for producing the optical fiber according to the present invention includes a drawing step of drawing an optical fiber preform in a drawing furnace to produce a silica glass-based optical fiber including a core region containing an alkali metal with an average concentration of 0.5 atomic ppm or more and a cladding region that surrounds the core region and a heating step of heating the optical fiber in a heating furnace through which the optical fiber drawn from the drawing furnace passes.

The present invention relates to a chemically strengthened glass having a first surface and a second surface facing the first surface, and having a compressive stress layer provided on the first surface and the second surface, in which a depth of compressive stress DOL.sub.1 (m) of the first surface is larger than a depth of compressive stress DOL.sub.2 (m) of the second surface, and a stress distribution in a sheet thickness direction of the chemically strengthened glass satisfies the following relational expression (1) and the following relational expression (3):

CT.sub.1/CT.sub.20.8(1)

and

CT.sub.1L.sup.1/230 (MPa.Math.mm.sup.1/2)(3).

An optical fiber has a core region that is doped with one or more viscosity-reducing dopants in respective amounts that are configured, such that, in a Raman spectrum with a frequency shift of approximately 600 cm.sup.1, the fiber has a nanoscale structure having an integrated D2 line defect intensity of less than 0.025. Alternatively, the core region is doped with one or more viscosity-reducing dopants in respective amounts that are configured such that the fiber has a residual axial compressive stress with a stress magnitude of more than 20 MPa and a stress radial extent between 2 and 7 times the core radius. According to another aspect of the invention a majority of the optical propagation through the fiber is supported by an identified group of fiber regions comprising the core region and one or more adjacent cladding regions. The fiber regions are doped with one or more viscosity-reducing dopants in respective amounts and radial positions that are configured to achieve viscosity matching among the fiber regions in the identified group.

One of embodiments relates to an optical fiber in which an alkali metal element is efficiently doped to its core to suppress transmission loss from increasing. A mean concentration or a concentration distribution of the alkali metal element is adjusted such that 0.48 or less is obtained as an weighted value obtained by weighting a distribution of field intensity of guided light at a wavelength of 1550 nm, with respect to a radial direction distribution of a ratio I.sub.D2/I.sub.3 of an intensity I.sub.D2 of Raman scattering light by a silica three-membered ring structure and an intensity I.sub.3 of Raman scattering light by a SiO stretching vibration, in a cross-sectional region having a diameter of 20 m.

A doping optimized single-mode optical fiber with ultra low attenuation includes a core layer and cladding layers. The cladding layers has 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 outer cladding layer. The content of fluorine in the core layer is 0.5 wt %, Ge0.12%, n.sub.10.12%. The content of fluorine in the inner cladding layer is 0.5-1.5 wt %, n.sub.20.14%. The content of fluorine in the trench cladding layer is 1-3 wt %, n.sub.30.25%. The content of fluorine in the auxiliary outer cladding layer is 0.5-2 wt %, n.sub.40.14%. The outer cladding layer is a pure silicon dioxide glass layer and/or a metal-doped silicon dioxide glass layer.

A glass article is designed at least in part in the form of a glass tube element including at least one shell which encloses at least one lumen. For at least one light transmission analysis of the glass article, a ratio of an average amplitude transmission factor and a specific amplitude transmission factor is greater than 1.00001.

Glass-based articles comprise stress profiles providing improved drop performance. A glass-based substrate comprises: a glass transition temperature (T.sub.g), a liquid fragility index (m), and fictive temperature (T.sub.f), wherein T.sub.g is less than or equal to 650 C., a value of T.sub.f minus T.sub.g is greater than or equal to 30 C., and m is greater than or equal to 25. A stress relaxation rate is greater than or equal to 10%, or 20% or more. The articles can comprise a lithium-based aluminosilicate composition and a fracture toughness that is greater than or equal to 0.75 MPa*m.sup.0.5. The stress profiles comprise: a spike region extending from the first surface to a knee; and a tail region extending from the knee to a center of the glass-based article, the tail region comprising: a negative curvature region wherein a second derivative of stress as a function of depth is negative; a depth of compression (DOC) that is greater than or equal to 0.22 t, and a parabolic region originating at the DOC and extending to the center of the glass-based article.