GLASS FOR OPTICAL TRANSMISSION BODY

摘要

PURPOSE: To provide a glass having weather resistance, crystal growth resistance and a high refractive index. CONSTITUTION: A basic compsn. consisting of 50-70mol% SiO2 , 15-25mol% B2 O3 and 15-25mol% Na2 O is prepd. and 4-15mol% ZnO and 1-9mol% ZrO2 are added to the basic compsn. so as to satisfy the relation of (ZnO/3)+(ZrO2 /2)<8.