I was chatting with my kids about how incandescent lightbulbs work, clarifying that they don't so much "burn very slowly" (their original understanding) so much as they emit photons "just like everything does when it gets hot" (my understanding of thermal electromagnetic radiation). Somehow water came up in the ensuing discussion and it got me wondering whether "water" could ever been seen to glow?
I found a thread on some more general forums on the topic that was a bit muddled but afaict one of the more proficient answers included this explanation:
Thus, the answer to “Will X glow at heat Y?” is only dependent on the Y. The only reason X might be an issue is that X may or may not exist at the temperature in question. (It’s kind of like Cecil’s answer on melting wood - long before it melts, it stops being what we’d call wood.)
…implying that at high temperatures the water would thermolyze into what I assume would just be "glowing hydrogen" and "glowing oxygen". But a later answer in that thread cites sources to claim that:
[…] you should be able to heat water to about the same color temperature as an incandescent light bulb, 2700-3300°K, before it starts dissociating.
Is this true? Can water molecules be hot enough to glow without breaking up? And if so, do they simply glow like e.g. hot steel would — or would its molecules still not behave like a "blackbody" under those conditions?