Patent ID: 7144835

Claim:
An aluminum-free borosilicate glass with chemical resistance and having a composition, in percent by weight, based on oxide content, of: SiO 2 67–75 B 2 O 3 9–18 Li 2 O 0–1 Na 2 O 0–3 K 2 O 5–10 with Li 2 O + Na 2 O + K 2 O 5.5–13.5 CaO 0–1 BaO 0–1 ZnO 0–1 TiO 2 0–1 ZrO 2 0.8–10.5 CeO 2 0–0.4 F − 0–0.6 and optionally at least one refining agent in a standard amount for refining.