Crystallization-resistant glass compositions suitable for manufacturing glass frits for microreactors

The invention is directed to a glass composition that can be used to make glass frits suitable for use in the manufacturingof microreactors. The glass compositions, after final sintering to produce afinished microreactor, have a surface crystalline layer of 30 mum or less, or are completely amorphous throughout. Generally, the borosilicate glasses of the invention have a composition of B 2 O 3 = 12 22 mol %;SiO 2 = 68 - 80 mol % andadditional components selected from the group consist -ing of either (a) Al2 O 3 = 3- 8 mol % and Li 2 O =1 - 8 mol %, or (b) K 2 O = 0 - 2 mol % andNa 2 O = 0 - 2 mol %, except that both K 2 O and Na 2 O cannot both equal zero at the same time. One borosilicate glass has a composition, in mole percent (mol%) of B 2 O 3 = 18 - 22 mol %, SkiO 2 = 75 - 80 mol %, K 2 O = 0 - 2 mol % and and Na 2 O = 0 - 2 mol %, except that both K 2 O and Na 2 O cannot both equal zero at the same time.