Effect of choice of alkali cation Flashcards
1
Q
What is viscosity a function of?
A
~ number of NBO’s formed
2
Q
What’s the effect of heavier cations?
A
~ heavier cations like Na+ and K+ give HIGHER DENSITY than with Li+
~ although K+ is heavier than Na+, it dialates the network more
~ the larger the cation, the greater the hard-sphere type ionic packing = higher CTE
3
Q
Why is the index of refraction of Li2O-Si2O higher?
A
> the small Li+ ions pull network ions closer together
higher conc of NBO give higher increase in index of refraction with R2O additions with Li2O