How much heat energy in molten glass?

[Jay Lakoda]

How much heat energy is in a cubic meter of molten glass?

I would like to know how much energy would be lost if a cubic meter of glass would be allowed to cool, instead of turning the energy into something else.

 

[Khashishi]

Depends on the temperature. Here's the specific heat capacity of (some kind of) glass at 20C. It probably changes as you go up in temperature, but this should get you a rough estimate.
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/sphtt.html

 

[Jay Lakoda]

Depends on the temperature. Here's the specific heat capacity of (some kind of) glass at 20C. It probably changes as you go up in temperature, but this should get you a rough estimate.
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/sphtt.html

Thank you =)

 

[CWatters]

Does glass have a latent heat of fusion/melting? Just wondering.

 

[Doug Huffman]

Hmm, I seem to recall glass characterized as a very viscous amorphous liquid, thus no phase change on solidification.

Some people claim that glass is actually a supercooled liquid because there is no first order phase transition as it cools. In fact, there is a second order transition between the supercooled liquid state and the glass state, so a distinction can still be drawn. The transition is not as dramatic as the phase change that takes you from liquid to crystalline solids. There is no discontinuous change of density and no latent heat of fusion. The transition can be detected as a marked change in the thermal expansivity and heat capacity of the material. [my emphasis]

http://math.ucr.edu/home/baez/physics/General/Glass/glass.html

 

[Vanadium 50]

Does glass have a latent heat of fusion/melting?

It does not. (But the "glass is a liquid" meme is an oversimplification designed more to produce a 'wow' than actual enlightenment)

 

[sophiecentaur]

It does not. (But the "glass is a liquid" meme is an oversimplification designed more to produce a 'wow' than actual enlightenment)

Also, there is a belief that the glass in old windows is thicker at the bottom than at the top because it has 'flowed downwards'. I think the reason is not to do with flowing but because the glass was always put in that way for strength.

 

[Doug Huffman]

All that is made clear in John Baez' article, the 'simplification' (of one only order phase transition) and mass orientation ("The sheets were thicker towards the edge of the disc and were usually installed with the heavier side at the bottom.").

But for strength?

 

[sophiecentaur]

[QUOTE="Doug Huffman, post: 4958953, member: 106968"
But for strength?/QUOTE]
Strength for two reasons. Handling is safer if you are holding the pane up to the space and shifting the pane around when it's resting on the ledge would de less risky.
Otoh it could be just cosmetic and putting the clearest bit up in the sky direction.