The glass for a fluorescent light with a high hydrolytic resistance, which has composition, in % by weight based on oxide content of: SiO2, 63-75; B2O3, 15-18; Al2O3, 2.5-4.5; Na2O, 0-10; K2O, 0-10; ΣNa2O+K2O, 2-10; MgO, 0-8; CaO, 0-10; SrO, 0-10; BaO, 0-10; ZnO, 0-5; ΣMgO+CaO+SrO+BaO+ZnO, 0-10; ZrO2, 0-3; CeO2, 0-10; Fe2O3, 0-1; WO3, 0-3; Bi2O3, 0-5; MoO3, 0-3; TiO2, 0-10; ΣHf+Ta+W+Re+Os+Ir+Pt+La+Pr+Nd+Sm+Eu+Gd+Tb+Dy+Ho+Er+Tm+Yb+Lu in oxidic form, 0 to 5% by weight, as well as one or more conventional refining agents. The glass is characterized in that it contains no lithium and has a weight ratio of Na2O to K2O of less than one.