[nekroa]

Hi there. Sorry for my ignorance but I'm a high school student and I have this very random question. Today I was working on my lab and I heated up my baking soda in my test tube, and my test tube began melting. I was astonished by this as I thought pyrex dont melt, so I tried heating up the test tube itself. However, there is no reaction when the test tube was heated for 15 minutes. I tried to use another compound along with the test tube, and the test tube began melting again. What's wrong? Does Pyrex not mix with compounds?

[AWK]

During sintering, Na2CO3 can reacts with borosilicate glass (pyrex) to form lower melting sodium borosilicate glass with much higher Na2O content ?