helpppp

Dear all, Hi!!This might seem a strange post on recreational glass group, but here goes....I am a graduate student in Bioengineering at Penn State and my research involves the usage of a glass bead to shape micropipettes. However, the glass bead which is used is made out of special glass which has a much lower temperature than the micropipette. In effect i am looking for a glass which can melt and flow at a temperature of around 450 degrees centigrade.The micropipettes are made of borosilicate and have a melting temperature of 700 degrees centigrade. I looked up a few compositions and also melted a few which contained boric oxide,silica and lead oxide(PbO).All i got out of them was a white looking ceramic and NO glass.I am quite desperate now and would like someone to point to me to any groups which are working in the field which develop low temperature melting glass or even any commercial resources.All i need is one low temperature melting glass bead, due to which my research has come to quite a standstill.I am just writing this on a lark and if anyone could give me some pointers on groups or resources which would enable me to obtain the same.I really thank you all for your. Regards Rama