Abstract: To provide a method for producing a fluorovinyl ether compound, whereby it is possible to suppress the generation of byproducts. The method for producing a fluorovinyl ether compound of the present invention is a method for producing a fluorovinyl ether compound, which comprises heat-treating a compound having a group represented by the formula (1): F—C(?O)—CF(X)—(CF2)n—O— in the presence of an oxide containing at least one element selected from the group consisting of alkali metal elements and alkaline earth metal elements, to obtain a fluorovinyl ether compound having a group represented by the formula (2): CF2?CF—O—, wherein the specific surface area of the oxide before the heat treatment is at least 1.0 m2/g. In the formula (1), n is 0 or 1, wherein when n is 0, X is CF3 and when n is 1, X is F.

Abstract: The present invention relates to a chemically strengthened glass having a first principal surface and a second principal surface facing the first principal surface, at least a portion of the first principal surface being chemically strengthened, wherein the depth of a compressive stress layer in at least a portion of the first principal surface continuously changes. This chemically strengthened glass can be suitably used in an application in which chemical strengthening characteristics that differ among different regions in the same plane are desired in a chemically strengthened glass.

Abstract: A glass sheet is a single glass sheet having a first surface and a second surface facing the first surface. The glass sheet has a curvature part curved in a first direction and a second direction orthogonal to the first direction. A radius of curvature in the first direction of the curvature part is 8,500 mm or less. At least a part of the first surface has been chemically strengthened in the curvature part. In the first direction within the chemically strengthened region in the curvature part, an Na amount in the first surface is smaller than the Na amount in the second surface.

Abstract: A glass sheet has one surface and the other surface facing the one surface in a thickness direction, wherein a fluorine concentration (average fluorine concentration by SIMS at a depth of 1 to 24 ?m) in the one surface is higher than that in the other surface. The following expression is satisfied: 0.07??F/?H2O. ?F (mol %) is a value obtained by subtracting an average fluorine concentration in the surface having the lower fluorine concentration from that in the surface having the higher fluorine concentration, and ?H2O (mol %) is an absolute value of a value obtained by subtracting an average H2O concentration in the surface having the higher fluorine concentration from that in the surface having the lower fluorine concentration.

Abstract: A glass sheet has one surface and the other surface facing the one surface in a thickness direction, wherein a fluorine concentration (average fluorine concentration by SIMS at a depth of 1 to 24 ?m) in the one surface is higher than that in the other surface. The following expression is satisfied: 0.07??F/?H2O. ?F (mol %) is a value obtained by subtracting an average fluorine concentration in the surface having the lower fluorine concentration from that in the surface having the higher fluorine concentration, and ?H2O (mol %) is an absolute value of a value obtained by subtracting an average H2O concentration in the surface having the higher fluorine concentration from that in the surface having the lower fluorine concentration.

Abstract: A glass sheet includes 4 mol % or more of Al2O3. In the glass sheet, a surface Na2O amount in one surface of the glass sheet is lower than the surface Na2O amount in the other surface of the glass sheet by 0.2 mass % to 1.2 mass %.