A glass composition includes: 50 mol % to 69 mol % SiO.sub.2; 12.5 mol % to 25 mol % Al.sub.2O.sub.3; 0 mol % to 8 mol % B.sub.2O.sub.3; greater than 0 mol % to 4 mol % CaO; greater than 0 mol % to 17.5 mol % MgO; 0.5 mol % to 8 mol % Na.sub.2O; 0 mol % to 2.5 mol % La.sub.2O.sub.3; and greater than 8 mol % to 18 mol % Li.sub.2O, wherein (Li.sub.2O+Na.sub.2O+MgO)/Al.sub.2O.sub.3 is from 0.9 to less than 1.3; and Al.sub.2O.sub.3+MgO+Li.sub.2O+ZrO.sub.2+La.sub.2O.sub.3+Y.sub.2O.sub.3 is from greater than 23 mol % to less than 50 mol %. The glass composition may be characterized by at least one of the following: a K.sub.1C value measured by a chevron short bar method of at least 0.75; and a K.sub.1C value measured by a double torsion method of at least 0.8. The glass composition is chemically strengthenable. The glass composition may be used in a glass article or a consumer electronic product.

A glass composition includes: 50 mol % to 69 mol % SiO.sub.2; 12.5 mol % to 25 mol % Al.sub.2O.sub.3; 0 mol % to 8 mol % B.sub.2O.sub.3; greater than 0 mol % to 4 mol % CaO; greater than 0 mol % to 17.5 mol % MgO; 0.5 mol % to 8 mol % Na.sub.2O; 0 mol % to 2.5 mol % La.sub.2O.sub.3; and greater than 8 mol % to 18 mol % Li.sub.2O, wherein (Li.sub.2O+Na.sub.2O+MgO)/Al.sub.2O.sub.3 is from 0.9 to less than 1.3; and Al.sub.2O.sub.3+MgO+Li.sub.2O+ZrO.sub.2+La.sub.2O.sub.3+Y.sub.2O.sub.3 is from greater than 23 mol % to less than 50 mol %. The glass composition may be characterized by at least one of the following: a K.sub.1C value measured by a chevron short bar method of at least 0.75; and a K.sub.1C value measured by a double torsion method of at least 0.8. The glass composition is chemically strengthenable. The glass composition may be used in a glass article or a consumer electronic product.

A glass powder composite includes a first glass powder, and a second glass powder having a different solubility from that of the first glass powder depending on pH, wherein both the first glass powder and the second glass powder have ion sustained-release properties.

An embodiment of the invention relates to a GI-MMF with a structure for achieving widening of bandwidth in a wider wavelength range and improving manufacturing easiness of a refractive index profile in a core. In an example of the GI-MMF, a whole region of the core is doped with Ge and a part of the core is doped with P. Namely, the Ge-doped region coincides with the whole region of the core and the Ge-doped region is comprised of a partially P-doped region doped with Ge and P; and a P-undoped region doped with Ge but not intentionally doped with P.

A manufacturing method for an optical fiber, includes: drawing, while heating in a heating furnace, a lower end of an optical fiber preform that is to be an optical fiber having a core consisting of silica glass containing a rare earth element compound. The heating furnace has a temperature profile in which a temperature of the heating furnace increases to a maximum temperature T.sub.max and then decreases from an upstream side of the heating furnace toward a downstream side of the heating furnace. The temperature profile has a changing point at which the temperature decreases more steeply on the downstream side from a position where the maximum temperature T.sub.max is reached. At the maximum temperature, a temperature of the silica glass is higher than or equal to a glass transition temperature and the silica glass is in a single phase.

Glass-based articles are manufactured by a unique ion exchange process that results in glass-based articles having improved stress profiles with higher stress values at moderate depths. A medium of the ion exchange process includes ions of two or more alkali metals of two or more alkali metal oxides in a base composition of a glass-based substrate in a ratio such that ions of each alkali metal are in chemical equilibrium with each of the respective alkali metals of the alkali metal oxides in the base glass composition.

A photodarkening-resistant ytterbium-doped quartz optical fiber and a method for prpearing such a fiber are provided. Glass of a photodarkening-resistant ytterbium-doped quartz optical fiber core rod includes at least Yb.sub.2O.sub.3, Al.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2. The proportions of Yb.sub.2O.sub.3, Al.sub.2O.sub.3, and P.sub.2O.sub.5 in the entire substance are Yb.sub.2O.sub.3: 0.05-0.3 mol %, Al.sub.2O.sub.3: 1-3 mol %, and P.sub.2O.sub.5: 1-5 mol %, respectively. In the preparation method for the photodarkening-resistant ytterbium-doped quartz optical fiber, a sol-gel method and an improved chemical vapor deposition method are combined. By using the molecular-level doping uniformity and the low preparation loss thereof respectively, ytterbium ions, aluminum ions and phosphorus ions are effectively doped in a quartz matrix, thereby effectively solving the problems in the optical fiber of high loss, photodarkening caused by cluster or the like, and a central refractive index dip.

Glass-based articles are manufactured by a unique ion exchange process that results in glass-based articles having improved stress profiles with higher stress values at moderate depths. A medium of the ion exchange process includes ions of two or more alkali metals of two or more alkali metal oxides in a base composition of a glass-based substrate in a ratio such that ions of each alkali metal are in chemical equilibrium with each of the respective alkali metals of the alkali metal oxides in the base glass composition.

The present application provides a process of fabrication of erbium and ytterbium-co-doped multielements silica glass based cladding-pumped fiber for use as a highly efficient high power optical amplifier.

Phosphate glasses and glass-ceramics exhibit a positive percent kill as measured by United States EPA Test Method for Efficacy of Copper Alloy Surfaces as a Sanitizer and/or have a CIELAB L* value below 35, CIELAB a* and b* values within 5 of zero.