Research Paper Help!

[Nicholas Propp]

Hey everybody!

Im writing a paper on glass history for a college class, and im trying to explain the difference between the COE of soft and hard glass. Such as which expands more/less, explaining how a specific COE makes it uncompatible with other COE, etc. Anything you guys got would be awesome. I think i got the most of it, just want to see what i may be missing. Thanks!!!

Cheers,
Nic

[emoon]

The reason different COE rated glasses are incompatible is because they cool at different rates, creating impossible stress loads within the bead, and forcing fractures. I know that there are probably more scientific souls out there that will give alot more than this, but, I hope it helps.

[Scooch]

Here is a link explaining COE.

http://en.wikipedia.org/wiki/Coeffic...rmal_expansion

The simple reason that different COEs are not compatable is because of the different rate and amount that they expand or contract according to temperature change for different COE. Since glass is a brittle material and is not flexible, this difference results in cracking.

[Bakerman44]

I'd love it if you posted your paper here for us to read! Good luck!

[cheng076]

Simply put, the Coefficient Of Expansion is a measure of the expansion of a material with changes in temperature. The number is increadably small; to the -7 power so COE 90 would be 0.0000090

Thus if two glasses of different COEs are fused together these different expansion rates or distances set up extremely high stress levels and since glass is so brittle these stresses cause shattering. At the molecular level glass is incredibly tough so small differences in COE may not cause enough stress to overcome the resistance of the glass and that is why using COE 96 frit on COE 104 glass as an example mostly works out.

PJH