My mother works in a ceramics workshop. Besides giving lessons she creates various ceramic dishes, cups and plates. She often uses the effect of colored glass melting in the product and then leaving beautiful patterns at the bottom.
However it always cracks a lot as cooling down. Sometimes, it looks good when it's cracked, but other times she's trying to make it look like a gem - and cracked gem is not very gemmy.
So I was curious if there is something non toxic, insoluble in water and alcohol, that would melt at the similar temperature as glass and would prevent it from cracking in the cool down phase.
The glass doesn't have to be temperature resistant in the final products. We just want to avoid the cracks