OPTICAL GLASS, HOT-FORMED ARTICLE AND METHOD FOR MANUFACTURING SAME, AND OPTICAL ELEMENT AND METHO

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An embodiment of the present invention relates to optical glass which comprises P2O5, B2O3 and a rare earth oxide as essential components, and in a glass composition on an oxide basis, the P2O5 content is in the range of over 0 mass% and less than 0.79 mass%, the B2O3 content is in the range of 20-40 mass% and the total content of the rare earth oxide and an oxide selected from the group consisting of Ta2O5, WO3, TiO2, Nb2O5 and Bi2O3 is in the range of 35-70 mass%. Further, this optical glass has a refractive index (nd) in the range of 1.72-1.83, an Abbe number (ʋd) in the range of 45-55 and a glass transition temperature (Tg) of 640°C or less.