Float glass plate and method of manufacturing thereof

1. A float glass plate that is formed by continuously supplying a molten glass onto a molten metal in a bath and allowing the molten glass to flow on the molten metal,

wherein the float glass plate satisfies the following expression (1) when, on a coordinate axis that is parallel to a through-thickness direction and has, as an origin, an arbitrary point on a principal surface which is positioned on the molten metal side in the bath among both principal surfaces of the float glass plate, a water concentration in glass at a coordinate x (μm) indicating a distance from the origin is represented by C(x) (mass ppm), the thickness of the float glass plate is represented by D (μm), a maximum value of the C(x) is represented by Ca (mass ppm), and a coordinate at which the C(x) is maximum is represented by Da (μm)

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2. The float glass plate according to claim 1 , wherein the thickness is 1.1 mm or less.

3. The float glass plate according to claim 1 , wherein the maximum value of the water concentration is 470 mass ppm or more.

4. The float glass plate according to claim 1 , which comprises an alkali-free glass that contains, by mass % in terms of oxides,

SiO 2 : 50 to 66%,

Al 2 O 3 : 10.5 to 24%,

B 2 O 3 : 0 to 12%,

MgO: 0 to 8%,

CaO: 0 to 14.5%,

SrO: 0 to 24%,

BaO: 0 to 13.5%,

MgO+CaO+SrO+BaO: 9 to 29.5%, and

ZrO 2 : 0 to 5%.

5. The float glass plate according to claim 4 , which comprises an alkali-free glass that contains, by mass % in terms of oxides,

SiO 2 : 58 to 66%,

Al 2 O 3 : 15 to 22%,

B 2 O 3 : 5 to 12%,

MgO: 0 to 8%,

CaO: 0 to 9%,

SrO: 3 to 12.5%,

BaO: 0 to 2%, and

MgO+CaO+SrO+BaO: 9 to 18%.