Abstract: An optical crown glass having a negative anomalous partial dispersion .DELTA.P.sub.g,F, a refractive index n.sub.d of greater than 1.52, an Abbe number .nu..sub.d of greater than 57, and a high UV transmission has a composition (in % by weight) 40-72 B.sub.2 O.sub.3, 9-31 Al.sub.2 O.sub.3, 0-15 SiO.sub.2, 0.1-0.5 H.sub.2 O, 0-12 Li.sub.2 O, wherein the total of R.sub.2 O (R=Li, Na, K, Rb, Cs) is 0-20 and the total of MO (M=Mg, Ca, Sr, Ba) is 0-30, and wherein the total of R.sub.2 O and MO is greater than 5, and the molar ratio between Al.sub.2 O.sub.3 and B.sub.2 O.sub.3 is 0.2-0.3 and the molar ratio between (R.sub.2 O+MO) and B.sub.2 O.sub.3 is 0.1-0.4.