| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical glass capable of obtaining a preform material which facilitates precision mold press molding and has high devitrification resistance at lower cost while a refractive index (n) and an Abbe number (&ngr;) are within a desired range, and to provide a preform material and an optical element.SOLUTION: An optical glass contains, by mol%, 10.0% or more and 50.0% or less of a BOcomponent and 5.0% or more and 30.0% or less of an LaOcomponent, has the total of mol (GdO+TaO) of less than 5.0%, has a refractive index (n) of 1.80 or more, and has an Abbe number (&ngr;) of 30 or more and 45 or less. |
