Provided is an alkali doping process of bringing a melt of an alkali metal compound or an alkaline earth metal compound into contact with a part of the inner circumferential surface of a silica glass tube, and thus doping the silica glass tube with the alkali metal compound or the alkaline earth metal compound, and in the alkali doping process, the contact location between the inner circumferential surface of the silica glass tube and the melt is moved along the longitudinal direction of the silica glass tube while rotating the silica glass tube around its longitudinal axis.

Provided is an optical fiber containing an alkali metal element or the like having a smaller diffusion coefficient than K and having a low Rayleigh scattering loss. An optical fiber is composed of silica glass and includes a core and a cladding arranged to surround the core which has a lower refractive index than the core. The core includes a first core including a central axis and a second core arranged to surround the first core. The average concentration of an alkali metal element or alkaline-earth metal element in the first core is 10 mol ppm or less. The average concentration of chlorine in the first core is 2000 mol ppm or more. The average concentration of an alkali metal element or alkaline-earth metal element in the second core is 10 mol ppm or more. The average concentration of chlorine in the second core is 10 to 600 mol ppm.

An optical fiber preform of the present embodiment comprises a core portion and a cladding each comprised of silica glass. The core portion has a first dopant region including a central axis of the core portion and a second dopant region away from the central axis. The first dopant region contains a first dopant selected from among Na, K, and their compounds, and a concentration of the first dopant is 10 atomic ppm or more but 2,000 atomic ppm or less. The second dopant region contains a second dopant reducing viscosity of the silica glass. The second dopant has, as a characteristic at a temperature of 2,000 C. to 2,300 C., a diffusion coefficient of 110.sup.12 cm.sup.2/s or higher but lower than that of the first dopant, and a concentration of the second dopant region is 10 atomic ppm or more.

An optical fiber containing alkali metal elements or the like in which Rayleigh scattering loss can be reduced is provided. An optical fiber includes a core composed of silica glass and a cladding which surrounds the core, has a refractive index lower than a refractive index of the core, and is composed of silica glass containing fluorine. The core contains a first group of dopants and a second group of dopants having a diffusion coefficient lower than a diffusion coefficient of the first group of dopants. The difference between the maximum value and the minimum value of residual stress in the optical fiber is 150 MPa or less.

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.

Silver sulfadiazine-immobilized inorganic fillers are described, and their synthesis is presented. The fillers are believed to have utility in dental composites and dental adhesives to achieve potent, long-term, and none-leaching antimicrobial effects.

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.

A colorless soda-lime glass composition comprising by weight from 68 to 78% SiO.sub.2, from 8 to 18% Na.sub.2O, from 0 to 10% K.sub.2O, from 7 to 12% CaO, from 0 to 10% MgO, from 0 to 10% ZnO, from 0 to 10% BaO, from 0 to 3% Al.sub.2O.sub.3, from 0 to 1% B.sub.2O.sub.3, from 0 to 1% SrO, less than 0.078% total sulfur expressed in the form of SO.sub.3, at most 0.12% total cerium expressed in the form of CeO.sub.2, from 50 to 1200 ppm total iron expressed in the form of Fe.sub.2O.sub.3, without the intentional addition of Mo, As, Sn and Sb species, and with a redox lower than 45.