I made it a little differently. Just edge blend alone gives you maximum glow at the outermost boundary, which is not realistic.

You need maximum glow near the surface, then fade out at the farthest edge.

Here's my render. I'll post the material file for this next.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)