blackthorn

Thanks everybody! I went looking for more information about my current clay, and there it was right in the description “granular manganese.” I also found some good tips about adding it to clay on DigitalFire. Time to buy some and do some tests. 
Sometimes the speckles in my current clay are unreasonably huge. I’ve even put some pots in the seconds pile because of weirdly large speckle splotches. So it might be nice improvement to have some control over the particle size now. 

A belated posting on this topic.
Before and after of cyanotype on bisque - and re-bisqued.
My next test will be reprinting and re-firing, however many times needed to get the iron to build up into a less subtle image.
 

A belated posting on this topic.
Before and after of cyanotype on bisque - and re-bisqued.
My next test will be reprinting and re-firing, however many times needed to get the iron to build up into a less subtle image.
 

Gotta love it!! Six----count 'em----SIX---- 25.75 inch shelves, stacked, are not that much higher than a standard computer mouse!! 

From what I found in my research on slumping glass onto ceramic substrates:
Fire the kiln to a temperature between 1200 to 1300°F (648.9 to 704.4°C), keeping an eye on the glass through the peephole.
The glass will begin softening and turn glossy when the temperature nears 1000°F (537.7°C) and start slumping as it nears 1200°F (648.9°C).
Sadly, I think this is much higher that the silver in Liquid Light can endure but have yet to confirm this.  It will likely dissapate above 1000ºF.
It's on my list to test but will require dedicated kiln time at the school and we're in the middle of a term with students scrambling like ferrets to have their work fired.
Still, sounds interesting and I'll pursue it as time permits.

I can attest that these are wonderful.  And another bit of technology I would be unwilling to be forego.
Good for you!
 

French butterdish is what I call them-no lawyers yet after 40 years. But wait there is still time  for them to line up out front.  Well they have to see them at a show or a shop. No online sales for me.
 

written on a typewriter.!
Marcia

From earlier today.
This will bisque to a light toasty brown.  Any higher and it will dissipate completely.
 

Reading just about any book on Ceramics will provide info on pigments that are used, and the better ones will describe the behavior of most at varying temperatures.
Since we know that:
"Glass melting is performed at temperatures between 700°C and 800 °C which correspond to an optimized value of the viscosity for glass refining and shaping",
we can surmise that firing an exposed and processed sheet of glass will begin to flux at temps nearing that.   Experimentation would be essential to see   1) How high is high enough to completely bond with the surface image;  2) How high is too high, which would result in partial or complete distortion of the image, ala Salvador Dali;  3) If it's even possible to sufficiently melt the glass without it bonding to whatever  cookie or shelving it's resting on during the firing.
 

@PeterH To your points 1 and 5 - I posted images of some of my recent tests earlier in this thread.  To your point 2 - I've found this to be true of fully vitrified stoneware and porcelain, so I coated it with a combination of equal parts of Whiting, Gesso and water.  It remains stable long enough to allow for exposure, processing and firing if it done within a day or two.  I haven't tried it yet but I'm also going to spray paint flat white, sand and repeat a few times, on a fully fired slab to see if it allows cyanotype to not bead up.  Gum or gelatin will bond to the painted and sanded surface. 

"What pigments that survive the heat" is an easy one: use ones in regular use in pottery. Such as "oxide-washes" and "ceramic stains".  @blackthorn mentioned some in one of his earlier posts. Often a little frit or Gertsey borate (or it's modern substitutes) is added to aid the fusion. Temperatures depend strongly on the glaze (or glass) you're fusing onto. Glaze choice constrained by the clay body of your "pot" (must match thermal expansions).
I've no idea if anybody has tried #5. You'll probably need to suck it and see ... or get lucky with literature-search/google. On the other hand if it doesn't work pretty much all avenues to fuse an "alternate photographic techniques" image to glaze/glass are probably doomed.
Parting thoughts
As stated pretty everywhere in these threads: test, test, test. Either it's a thought-experiment or you need to start making & firing at least some test-pieces. Perhaps join a local studio and get a little hands-on experience, and contact with potters at work.
You also will only succeed if you can get all the stages (including exposing the  3d object) working right. A chain is as strong as its weakest link, and all that.
Obviously you need to safely manage any fumes arising during firing.
... and I should have said that mixed-media is a legitimate choice if it satisfies your objectives. So covering an image on a porous pot with some sort of sealer might meet your needs (varnish, brick sealer, clear paint, ...) and would save a lot of hands-on learning pottery 101+. Or act as a stepping stone to greater things.

There seems to be a degree of mutual confusion. I'll explain my thoughts.
Decomposition temperatures
1) If you use a method like pigment-loaded gum-dichromate (or gum-DAS) after exposure and development you finish up with an image consisting of varying thickness of pigment-loaded "gum".
2) Essentially you have created a "transfer" in-situ. Either sitting on top of a glass/glaze or within the top layers of a porous ceramic.
3) At this point the dichromate/DAS has served its purpose, and can be burned-out with the gum during the firing.
4) Hopefully the pigment will stay in sufficiently close proximity to the surface to be fused/incorporated into it during the firing.
There is absolutely no need to look for light-sensitive materials with a high decomposition temperature for this process.
Cyanotype
You state that cyanotype "can be fired to ceramic but not to glass", a reference for this would aid the discussion. But here we go:
1) The cyanotype process precipitates out a strongly coloured iron compound, which forms a strong image. If fired this will decompose to a paler iron oxide. Here are some pix of the unfired image. I've yet to see any pix of fired image. https://tinyurl.com/8ubba93x
2) Legalistic quibble. The initial cyanotype process was a liquid process and relied on the backing material (paper,cloth, etc) to hold the precipitated compound in place. This carries over naturally to porous ceramic but not to water-proof glass/glaze.
3) A long-standing solution to this problem is the precipitate the iron compound into a layer of gelatin or similar. https://tinyurl.com/ynhzneer
4) If you want a fired-on image from such cyanotype I would just try firing them. The situation is not that different from transfers or gum-DAS images so the chances of it working are promising.
5) Do we know anybody who has tried this? How successful was the attempt?
Finally photo-sensitive glass
This presents a completely different and formidable set of challenges.  Which I'll comment on in a separate posting.

Absolutely Peter.  Iron, Cobalt, Manganese all can be and are used as pigment in gelatin or gum dichro printing. 
The ONLY thing one has to watch out for it the amount used.  I can attest to the fact that if too much of any of these is used then the emulsion becomes to opaque, like parts of the negative and blocks the exposure.  So much of the emulsion simply washes away after exposure.  Less is more with both oxides and Mason Stains and interestingly enough, that includes Mason Stain White, which I've used with film positives on dark clay bodies, instead of a film negative.
But, @jsmoove, your point about testing is, of course, correct.  I'm still doing that.  I've found many ways how not to make these processes work.
I have no experience with glass work but admire the process.  There are only so many hours for me and that's another rabbit hole in which I could easily get lost.

Absolutely Peter.  Iron, Cobalt, Manganese all can be and are used as pigment in gelatin or gum dichro printing. 
The ONLY thing one has to watch out for it the amount used.  I can attest to the fact that if too much of any of these is used then the emulsion becomes to opaque, like parts of the negative and blocks the exposure.  So much of the emulsion simply washes away after exposure.  Less is more with both oxides and Mason Stains and interestingly enough, that includes Mason Stain White, which I've used with film positives on dark clay bodies, instead of a film negative.
But, @jsmoove, your point about testing is, of course, correct.  I'm still doing that.  I've found many ways how not to make these processes work.
I have no experience with glass work but admire the process.  There are only so many hours for me and that's another rabbit hole in which I could easily get lost.

Absolutely Peter.  Iron, Cobalt, Manganese all can be and are used as pigment in gelatin or gum dichro printing. 
The ONLY thing one has to watch out for it the amount used.  I can attest to the fact that if too much of any of these is used then the emulsion becomes to opaque, like parts of the negative and blocks the exposure.  So much of the emulsion simply washes away after exposure.  Less is more with both oxides and Mason Stains and interestingly enough, that includes Mason Stain White, which I've used with film positives on dark clay bodies, instead of a film negative.
But, @jsmoove, your point about testing is, of course, correct.  I'm still doing that.  I've found many ways how not to make these processes work.
I have no experience with glass work but admire the process.  There are only so many hours for me and that's another rabbit hole in which I could easily get lost.

Mark's comment on eating Fair food and getting ill reminded me of the time I got food poisoning and my wife had to do the tear down and packing all by herself as I writhed, sweating in agony.  Subsequently I planned my fasts around events and just drank tea and water.  Two or three days was not a struggle.  Not a very exciting response to the original question I suppose but there it is.  I'm extremely unlikely to eat street vendor food from any location ever again.

I'm being very careful to say as little as possible, in order not to mislead you. I'm  just indicating further research might be worthwhile.
If the transfer paper was much cheaper, I'd suggest doing  a trial transfer with it to see how "archival" the the fused image is. [But I believe that not all toners contain iron.]
If it turned out well it's likely a proof-of-concept that a refractory powder can be fused onto glass, with the burn-out of a carrier (plastic in the case of toner?).

@jsmoove
My background is also in photography and my projects of late have revolved around getting a stable photographic image on ^10 ceramics.  I've not tried any glass work but am having plenty of success with a handful of techniques, most of which involve direct contact exposure with a large format negative.  
I've previously posted a few imageson the forum here so won't take up additional space re-posting those but the ones here are more recent takes on the two most successful techniques: cyanotype and gum bichromate.
Cyanotype is lovely, both unfired and fired.  Although it's main light sensitive constituent is iron, the iron is fugitive at higher temps.  I've not yet tested it's high limit but at bisque it comes off a nice toasty brown.
The gum bichromate is just like the paper print process though instead of watercolor pigment typically used, I mix mason stains or Manganese Dioxide with either Gerstley Borate, Frit 3124 or some clear glaze recipe as a binder.  
So far all of my tests are on slabs but I'm constructing an exposure unit that will allow for 360 degree exposure for taller thrown work.
I know it's a bit off topic from the ground glass rod query in the op but it does speak to the process of fixing true photographic images onto a ceramic substrate.
There are a couple of other processes I'm exploring but the results have been a bit weak so far, but still have some possibilities.  Happy to discuss if you're interested.

As for the cyanide gas release during the firing, yes, the kiln is outdoors and well away from any human traffic.  Even so, the amount of hydrogen cyanide is really quite small given the coverage of the pieces you see above.
As you say, you want to render your image permanent on the glass.  Firing is both unnecessary and most likely ruinous.  In order to use glass as an initial substrate like the fellow in the link below the glass has to be of reasonable thickness to allow for handling as well as support of the image.  That would make it at the very least 1/16th of in inch thick.  Regardless of how the image is affixed to the glass when is fired that image will most likely go all Salvador Dali and become unrecognizable.  Could be interesting but it's a grand toss up.
As you mentioned wanting to commit your artwork to glass specifically, so here are some links to two fellows doing just that.  Keep in mind that their works are finished pieces and would never survive a firing at any temp.  And your point about the Liquid Light is true, given the melting point of Silver Nitrate is something you can accomplish in your household oven, right around 450º F.
There are a few ways to render a permanent image on high or low fired ceramic surface but to the very best of my knowledge they don't involve an initial glass substrate.  Then again, I could be wrong.
Here are ways to render images on glass pretty permanently  - without firing:
 
Cyanotype on glass:
 
Carbon Transfer Printing on Glass:
 
 
 

@blackthorn, your ^10 cyanotype + white underglaze looks like fossil dug up from an excavation. Neat stuff! Thanks for sharing your process and results.

@jsmoove
My background is also in photography and my projects of late have revolved around getting a stable photographic image on ^10 ceramics.  I've not tried any glass work but am having plenty of success with a handful of techniques, most of which involve direct contact exposure with a large format negative.  
I've previously posted a few imageson the forum here so won't take up additional space re-posting those but the ones here are more recent takes on the two most successful techniques: cyanotype and gum bichromate.
Cyanotype is lovely, both unfired and fired.  Although it's main light sensitive constituent is iron, the iron is fugitive at higher temps.  I've not yet tested it's high limit but at bisque it comes off a nice toasty brown.
The gum bichromate is just like the paper print process though instead of watercolor pigment typically used, I mix mason stains or Manganese Dioxide with either Gerstley Borate, Frit 3124 or some clear glaze recipe as a binder.  
So far all of my tests are on slabs but I'm constructing an exposure unit that will allow for 360 degree exposure for taller thrown work.
I know it's a bit off topic from the ground glass rod query in the op but it does speak to the process of fixing true photographic images onto a ceramic substrate.
There are a couple of other processes I'm exploring but the results have been a bit weak so far, but still have some possibilities.  Happy to discuss if you're interested.

@jsmoove
My background is also in photography and my projects of late have revolved around getting a stable photographic image on ^10 ceramics.  I've not tried any glass work but am having plenty of success with a handful of techniques, most of which involve direct contact exposure with a large format negative.  
I've previously posted a few imageson the forum here so won't take up additional space re-posting those but the ones here are more recent takes on the two most successful techniques: cyanotype and gum bichromate.
Cyanotype is lovely, both unfired and fired.  Although it's main light sensitive constituent is iron, the iron is fugitive at higher temps.  I've not yet tested it's high limit but at bisque it comes off a nice toasty brown.
The gum bichromate is just like the paper print process though instead of watercolor pigment typically used, I mix mason stains or Manganese Dioxide with either Gerstley Borate, Frit 3124 or some clear glaze recipe as a binder.  
So far all of my tests are on slabs but I'm constructing an exposure unit that will allow for 360 degree exposure for taller thrown work.
I know it's a bit off topic from the ground glass rod query in the op but it does speak to the process of fixing true photographic images onto a ceramic substrate.
There are a couple of other processes I'm exploring but the results have been a bit weak so far, but still have some possibilities.  Happy to discuss if you're interested.