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.

The present invention relates to a glass for chemical strengthening including, in mole percentage on an oxide basis: 45 to 75% of SiO.sub.2; 1 to 30% of Al.sub.2O.sub.3; 1 to 20% of Li.sub.2O; 0 to 5% of Y.sub.2O.sub.3; 0 to 5% of ZrO.sub.2; and 0 to 1% of TiO.sub.2, having a total content of one or more kinds of MgO, CaO, SrO, BaO and ZnO of 1 to 20%, having a total content of Na.sub.2O and K.sub.2O of 0 to 10%, having a total content of B.sub.2O.sub.3 and P.sub.2O.sub.5 of 0 to 10%, and having a value M expressed by the following expression of 1,000 or more: M=−5×[SiO.sub.2]+121×[Al.sub.2O.sub.3]+50×[Li.sub.2O]−35×[Na.sub.2O]+32×[K.sub.2O]+85×[MgO]+54×[CaO]−41×[Sr O]−4×[P.sub.2O.sub.5]+218×[Y.sub.2O.sub.3]+436×[ZrO.sub.2]−1180, in which each of [SiO.sub.2], [Al.sub.2O.sub.3], [Li.sub.2O], [Na.sub.2O], [K.sub.2O], [MgO], [CaO], [SrO], [P.sub.2O.sub.5], [Y.sub.2O.sub.3], and [ZrO.sub.2] designates a content of each component in mole percentage on an oxide basis.

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.

The present invention relates to a glass for chemical strengthening including, in mole percentage on an oxide basis: 60 to 72% of SiO.sub.2; 9 to 20% of Al.sub.2O.sub.3; 1 to 15% of Li.sub.2O; 0.1 to 5% of Y.sub.2O.sub.3; 0 to 1.5% of ZrO.sub.2; and 0 to 1% of TiO.sub.2, having a total content of one or more kinds of MgO, CaO, SrO, BaO and ZnO of 1 to 10%, having a total content of Na.sub.2O and K.sub.2O of 1.5 to 10%, having a total content of B.sub.2O.sub.3 and P.sub.2O.sub.5 of 0 to 10%, wherein a ratio ([Al.sub.2O.sub.3]+[Li.sub.2O])/([Na.sub.2O]+[K.sub.2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO]+[ZrO.sub.2]+[Y.sub.2O.sub.3]) is from 0.7 to 3, wherein a ratio [MgO])/([CaO]+[SrO]+[BaO]+[ZnO]) is from 10 to 45, and having a value M expressed by the following expression of 1,100 or more:

M=−5×[SiO.sub.2]+121×[Al.sub.2O.sub.3]+50×[Li.sub.2O]−35×[Na.sub.2O]+32×[K.sub.2O]+85×[MgO]+54×[CaO]−41×[SrO]−4×[P.sub.2O.sub.5]+218×[Y.sub.2O.sub.3]+436×[ZrO.sub.2]−1180, wherein each of [SiO.sub.2], [Al.sub.2O.sub.3], [Li.sub.2O], [Na.sub.2O], [K.sub.2O], [MgO], [CaO], [SrO], [P.sub.2O.sub.5], [Y.sub.2O.sub.3], and [ZrO.sub.2] designates a content of each component in mole percentage on an oxide basis.

An optical glass includes, in terms of mol % of cations, a total amount of La.sup.3+, Y.sup.3+, and Gd.sup.3+ components falling within a range of from 5% to 65% and a total amount of Zr.sup.4+, Hf.sup.4+, and Ta.sup.5+ components failing within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La.sup.3++Y.sup.3++Gd.sup.3+)×(Zr.sup.4+ Hf.sup.4++Ta.sup.3+)≥400(%).sup.2.

The present invention relates to a glass for chemical strengthening including, in mole percentage on an oxide basis: 60 to 72% of SiO.sub.2; 9 to 20% of Al.sub.2O.sub.3; 1 to 15% of Li.sub.2O; 0.1 to 5% of Y.sub.2O.sub.3; 0 to 1.5% of ZrO.sub.2; and 0 to 1% of TiO.sub.2, having a total content of one or more kinds of MgO, CaO, SrO, BaO and ZnO of 1 to 10%, having a total content of Na.sub.2O and K.sub.2O of 1.5 to 10%, having a total content of B.sub.2O.sub.3 and P.sub.2O.sub.5 of 0 to 10%, wherein a ratio ([Al.sub.2O.sub.3]+[Li.sub.2O])/([Na.sub.2O]+[K.sub.2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO]+[ZrO.sub.2]+[Y.sub.2O.sub.3]) is from 0.7 to 3, wherein a ratio [MgO])/([CaO]+[SrO]+[BaO]+[ZnO]) is from 10 to 45, and having a value M expressed by the following expression of 1,100 or more:
M=−5×[SiO.sub.2]+121×[Al.sub.2O.sub.3]+50×[Li.sub.2O]−35×[Na.sub.2O]+32×[K.sub.2O]+85×[MgO]+54×[CaO]−41×[SrO]−4×[P.sub.2O.sub.5]+218×[Y.sub.2O.sub.3]+436×[ZrO.sub.2]−1180, wherein each of [SiO.sub.2], [Al.sub.2O.sub.3], [Li.sub.2O], [Na.sub.2O], [K.sub.2O], [MgO], [CaO], [SrO], [P.sub.2O.sub.5], [Y.sub.2O.sub.3], and [ZrO.sub.2] designates a content of each component in mole percentage on an oxide basis.

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.

An optical glass includes, in terms of mol % of cations, a total amount of La.sup.3+, Y.sup.3+, and Gd.sup.3+ components falling within a range of from 5% to 65% and a total amount of Zr.sup.4+, Hf.sup.4+, and Ta.sup.5+ components falling within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La.sup.3++Y.sup.3++Gd.sup.3+)×(Zr.sup.4++Hf.sup.4++Ta.sup.5+)≥400 (%).sup.2

The present invention relates to a glass for chemical strengthening including, in mole percentage on an oxide basis: 45 to 75% of SiO.sub.2; 1 to 30% of Al.sub.2O.sub.3; 1 to 20% of Li.sub.2O; 0 to 5% of Y.sub.2O.sub.3; 0 to 5% of ZrO.sub.2; and 0 to 1% of TiO.sub.2, having a total content of one or more kinds of MgO, CaO, SrO, BaO and ZnO of 1 to 20%, having a total content of Na.sub.2O and K.sub.2O of 0 to 10%, having a total content of B.sub.2O.sub.3 and P.sub.2O.sub.5 of 0 to 10%, and having a value M expressed by the following expression of 1,000 or more: M=5[SiO.sub.2]+121[Al.sub.2O.sub.3]+50[Li.sub.2O]35[Na.sub.2O]+32[K.sub.2O]+85[MgO]+54[CaO]41[Sr O]4[P.sub.2O.sub.5]+218[Y.sub.2O.sub.3]+436[ZrO.sub.2]1180, in which each of [SiO.sub.2], [Al.sub.2O.sub.3], [Li.sub.2O], [Na.sub.2O], [K.sub.2O], [MgO], [CaO], [SrO], [P.sub.2O.sub.5], [Y.sub.2O.sub.3], and [ZrO.sub.2] designates a content of each component in mole percentage on an oxide basis.

An optical glass includes, in terms of mol % of cations, a total amount of La.sup.3+, Y.sup.3+, and Gd.sup.3+ components falling within a range of from 5% to 65% and a total amount of Zr.sup.4+, Hf.sup.4+, and Ta.sup.5+ components failing within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La.sup.3++Y.sup.3++Gd.sup.3+)(Zr.sup.4+Hf.sup.4++Ta.sup.3+) 400(%).sup.2