Well, it won't kill you right away, but it would certainly harm you.
Remember that, when microwave heats up things, the heat is not even. If you put a soup bowl or big cup of water in the microwave and heat it for 1-2 minutes, then you can tell that certain part of the content is hotter than the other. This is very bad for the chemicals. Imagine that the outer part of the chemicals are already 110F degree, but it is only 80F in the middle. I just do now know what is going to happen to the chemicals.
Use hot water and maybe a water heater, but skip the microwave for the reasons mentioned above and because a microwave will not give you the control over the temperature that you need.
Thank you all for your input....yeah, a hot water bath seems the way to go..tnx again!
I have a darkroom microwave, vented as the sink is vented.
Very handy to heat previously boiled and stored R/O water when mixing a developer or fixer up up.
I have used this microwave to to heat up colur chems. I do it in 20 second bursts, and swirl the liquid in between.
You will find that blixes, with all the ferri in them, seem to heat very quickly; much faster than water it seems to me.
I use my microwave for my RA4 chemicals. Same one that I use for my food. The containers I use are only used for chemistry.
I don't worry about fumes / vapours. Microwaves aren't sealed units. Otherwise they would be a pressure cooker and you would probably have stream burns every time you opened it up.
They vent the air out the back. Or in my case, into the venting for my range fan.
Thanks for the additional input...yeah even processing chemistry that isn't heated (ie. B/W) produces some fumes I would think heating only increases it. The vent fan in the small bathroom I use for a darkroom can only do so much. (And when I print I can't have it running or I won't hear the timer....usually run it after the session)