Glass, chemically strengthened glass, and method for producing glass having curved shape

A glass wherein:

• the glass is a crystallized glass;
• the glass has a difference log η−log η0 (dPa·s) between a logarithm log η(dPa·s) of bulk viscosity η (dPa·s) defined below and a logarithm log η0 (dPa·s) of local viscosity no (dPa·s) defined below of larger than 0 and 1.8 or smaller, in a temperature range in which the logarithm log η(dPa·s) of the bulk viscosity η (dPa·s) is 11.4 or larger and 12.7 or smaller,
• bulk viscosity η:
• viscosity of the entire glass measured by a penetration method or a parallel plate method,
• local viscosity η0:
• viscosity of an amorphous portion of the glass determined according to the following Equation (1) in a case where a crystallinity of the glass is 0.4 or lower, and according to the following Equation (2) in a case where the crystallinity of the glass is larger than 0.4, from the bulk viscosity and a volume fraction of particles;
• and
• in the following Equation (1), d is an average particle diameter, Sr is a specific surface area of particles per unit volume, φv is a volume concentration, and φve is a marginal maximum volume concentration;
• in the following Equation (2), φv is a volume concentration;
• and in each of the following Equations (1) and (2), in a case of a crystallized glass, the volume concentration represented by φv means crystallinity:
• η
• η
• 0
• =
• 1
• +
• d
• ·
• S
• r
• 2
• ·
• 1
• 1
• /
• φ
• v
• -
• 1
• /
• φ
• vc
• =
• 1
• +
• 3
• 1
• /
• φ
• v
• -
• 1
• /
• 0.52
• (
• 1
• )
• η
• η
• 0
• =
• (
• 1
• -
• φ
• v
• )
• -
• 2.5
• .
• (
• 2
• )