1. How many grams of BaO can be added to 1 kg of SiO2 before the O:Si ratio exceeds 2.5 and glass-forming tendencies are poor? Compare this with the case when Li2O is added to SiO2.
2. Calculate the O:Si ratio when 30 wt% Y2O3 is added to SiO2. Will this material provide good glass-forming tendencies?