To provide a press molding glass material which enables to obtain a glass molded body of a desired shape while suppressing fusion to a molding die regardless of glass deformation volume in press molding.
The press molding glass material includes: a core portion composed of optical glass; and a surface layer covering the core portion. The surface layer includes an outermost layer contacting with a molding surface of a molding die in press molding and an intermediate layer adjacent to the outmost layer, the outermost layer is a silicon oxide film having a surface free energy measured by a three-solution method of ≤75 mJ/m2 and having a film thickness of <15 nm, and the intermediate layer is a film composed of a film material having a bond-radius difference from a silicon oxide based on a stoichiometric composition of >0.10 Å, wherein in a case in which the bond-radius difference is >0.10 to 0.40 Å, a film thickness of the intermediate layer is ≤5 nm.
YASUHIKO KENYA
JP2011001259A | 2011-01-06 | |||
JP2005239434A | 2005-09-08 | |||
JP2004075529A | 2004-03-11 |