High strength glass having improved mechanical characteristics

A thermally strengthened glass sheet:

• the glass sheet having a thickness, expressed in millimeters, of t, a length, expressed in millimeters, of l, and a width, expressed in millimeters, of w, t being less than l and less than w;
• the glass sheet having a first major surface and a second major surface separated by the thickness t;
• the glass sheet comprising a glass having a low temperature linear CTE, expressed in 1/° C., of αSCTE, a high temperature linear CTE, expressed in 1/° C., of αLCTE, an elastic modulus, expressed in GPa, of E, a strain temperature, expressed in units of ° C., of Tstrain, and a softening temperature, expressed in units of ° C., of Tsoft;
• the first major surface of the glass sheet having a thermally induced surface compressive stress of less than 600 MPa and greater than
• P
• 1
• ⁡
• (
• h
• )
• *
• t
• (
• P
• 2
• ⁡
• (
• h
• )
• +
• t
• )
• ·
• E
• ·
• [
• T
• strain
• ·
• α
• CTE
• s
• +
• α
• CTE
• L
• ·
• (
• T
• soft
• -
• T
• strain
• )
• ]
• ;
• in units of MPa;
• wherein P1 is given by
• 910.2
• -
• 259.2
• ·
• exp
• ⁡
• (
• -
• h
• 0.143
• )
• ;
• P2 is given by
• 2.53
• +
• 23.65
• (
• 1
• +
• (
• h
• 0.00738
• )
• 1.58
• )
• ;
• and h is greater than or equal to 0.020,
• wherein the first major surface a roughness in the range of from 0.2 to 0.4 nm Ra over an area of 10 μm×10 μm.