Corning Incorporated
STRESS PROFILES OF GLASS-BASED ARTICLES HAVING IMPROVED DROP PERFORMANCE

Abstract:

Glass-based articles comprise stress profiles providing improved drop performance. A glass-based substrate comprises: a glass transition temperature (T.sub.g), a liquid fragility index (m), and fictive temperature (T.sub.f), wherein T.sub.g is less than or equal to 650.degree. C., a value of T.sub.f minus T.sub.g is greater than or equal to -30.degree. C., and m is greater than or equal to 25. A stress relaxation rate is greater than or equal to 10%, or 20% or more. The articles can comprise a lithium-based aluminosilicate composition and a fracture toughness that is greater than or equal to 0.75 MPa*m.sup.0.5. The stress profiles comprise: a spike region extending from the first surface to a knee; and a tail region extending from the knee to a center of the glass-based article, the tail region comprising: a negative curvature region wherein a second derivative of stress as a function of depth is negative; a depth of compression (DOC) that is greater than or equal to 0.22t, and a parabolic region originating at the DOC and extending to the center of the glass-based article.