A glass for chemical strengthening has a Young's modulus E of 70 GPa or more. The glass satisfies X.sub.1+X.sub.2+X.sub.3 being 1760 or less. Here, X.sub.1 is a numerical value equivalent to a value [unit: kPa/° C.] obtained by multiplying the Young's modulus E by an average coefficient α of thermal expansion at 50° C. to 350° C., X.sub.2 is a numeral value equivalent to a value of a temperature Tf [unit: ° C.] at which a viscosity of the glass reaches 100 MPa.Math.s, and X.sub.3 is a numerical value equivalent to a value of a difference [unit: 10.sup.5 Pa.Math.s] between the viscosity (100 MPa.Math.s) at the Tf and a viscosity η.sub.+10 at a temperature 10° C. higher than the Tf.

A glass for chemical strengthening has a Young's modulus E of 70 GPa or more. The glass satisfies X.sub.1+X.sub.2+X.sub.3 being 1760 or less. Here, X.sub.1 is a numerical value equivalent to a value [unit: kPa/° C.] obtained by multiplying the Young's modulus E by an average coefficient α of thermal expansion at 50° C. to 350° C., X.sub.2 is a numeral value equivalent to a value of a temperature Tf [unit: ° C.] at which a viscosity of the glass reaches 100 MPa.Math.s, and X.sub.3 is a numerical value equivalent to a value of a difference [unit: 10.sup.5 Pa.Math.s] between the viscosity (100 MPa.Math.s) at the Tf and a viscosity η.sub.+10 at a temperature 10° C. higher than the Tf.

A glass-ceramic article includes a crystalline phase; a residual glass phase; greater than or equal to 52 mol % and less than or equal to 70 mol % SiO.sub.2, greater than or equal to 14 mol % and less than or equal to 35 mol % Li.sub.2O, greater than or equal to 0.1 mol % and less than or equal to 15 mol % CaO, greater than or equal to 0.5 mol % and less than or equal to 10 mol % ZrO.sub.2; and greater than or equal to 0.5 mol % and less than or equal to 5 mol % P.sub.2O.sub.5.

A colored glass article includes from 40 mol % to 70 mol % SiO.sub.2; from 8 mol % to 20 mol % Al.sub.2O.sub.3; from 1 mol % to 10 mol % B.sub.2O.sub.3; from 1 mol % to 20 mol % Li.sub.2O; from 1 mol % to 15 mol % Na.sub.2O; from 0 mol % to 8 mol % MgO; from 0 mol % to 5 mol % ZnO; and from 0.0005 mol % to 1 mol % Au. MgO+ZnO is from 0.1 mol % to 6 mol %.

A glass composition includes: greater than or equal to 55 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 14 mol % and less than or equal to 25 mol % Al.sub.2O.sub.3; greater than or equal to 0 mol % B.sub.20.sub.3; greater than or equal to 0 mol % P.sub.2O.sub.5; greater than or equal to 0 mol % and less than or equal to 10 mol % Li.sub.2O; greater than or equal to 6.5 mol % and less than or equal to 20 mol % Na.sub.2O; greater than or equal to 0 mol % K.sub.2O; greater than or equal to 0.1 mol % and less than or equal to 4.5 mol % MgO; greater than or equal to 0 mol % CaO; and greater than or equal to 0 mol % SrO. The sum of Li.sub.2O, Na.sub.2O, and K.sub.2O in the glass composition may be greater than or equal to 6.5 mol % and less than or equal to 22 mol %. The glass composition may satisfy the relationship Al.sub.2O.sub.3*(2.94)+B.sub.2O.sub.3*(−0.58)+P.sub.2O.sub.5*(−3.87)+Li.sub.2O*(5.01)+Na.sub.2O*(1.89)+K.sub.2O*(−2.03) is greater than 100.

A glass composition includes: greater than or equal to 55 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 14 mol % and less than or equal to 25 mol % Al.sub.2O.sub.3; greater than or equal to 0 mol % B.sub.20.sub.3; greater than or equal to 0 mol % P.sub.2O.sub.5; greater than or equal to 0 mol % and less than or equal to 10 mol % Li.sub.2O; greater than or equal to 6.5 mol % and less than or equal to 20 mol % Na.sub.2O; greater than or equal to 0 mol % K.sub.2O; greater than or equal to 0.1 mol % and less than or equal to 4.5 mol % MgO; greater than or equal to 0 mol % CaO; and greater than or equal to 0 mol % SrO. The sum of Li.sub.2O, Na.sub.2O, and K.sub.2O in the glass composition may be greater than or equal to 6.5 mol % and less than or equal to 22 mol %. The glass composition may satisfy the relationship Al.sub.2O.sub.3*(2.94)+B.sub.2O.sub.3*(−0.58)+P.sub.2O.sub.5*(−3.87)+Li.sub.2O*(5.01)+Na.sub.2O*(1.89)+K.sub.2O*(−2.03) is greater than 100.

Glass fibers formed from the inventive composition may be used in applications that require high stiffness and have a specific modulus between 34 and 40 MJ/kg. Such applications include woven fabrics for use in forming wind turbine blades and aerospace structures.

Glass fibers formed from the inventive composition may be used in applications that require high stiffness and have a specific modulus between 34 and 40 MJ/kg. Such applications include woven fabrics for use in forming wind turbine blades and aerospace structures.

A method of manufacturing a glass article includes a forming step of causing a first molten glass (Gm1) including P.sub.2O.sub.5 to flow down along a surface of a forming trough (15) including an yttrium-containing oxide by a down-draw method to form a glass ribbon (G), wherein the forming trough (15) includes a Mg-rich layer (MR) serving as a diffusion suppression layer for suppressing diffusion of the yttrium-containing oxide on the surface thereof.

A method of manufacturing a glass article includes a forming step of causing a first molten glass (Gm1) including P.sub.2O.sub.5 to flow down along a surface of a forming trough (15) including an yttrium-containing oxide by a down-draw method to form a glass ribbon (G), wherein the forming trough (15) includes a Mg-rich layer (MR) serving as a diffusion suppression layer for suppressing diffusion of the yttrium-containing oxide on the surface thereof.