i tried it once and sparks started flying and burned a hole right through my handle like a lightning strike. no joke. i probably did it for too long though
Nah, it was not that you had it in too long. There was probably metal, like foil in the logo on the handle.
Not really that intelligent to put a wood racket in a microwave though. It probably would not do anything but waste electricity. But, if the blade you have, has metal in it, you are not supposed to put metal in a microwave. Things like what cmetsbeltran15 describes could happen.
But from a theoretical standpoint, a microwave should not do much of anything to a block of wood. This could be tested and I could be wrong. But if you put a plastic bowl in microwave oven and set the microwave for 30-60 seconds, it should not heat the plate at all. This is because the microwave works with substances that are liquid by making the molecules move faster. This is how the substance heats up. This is also why, when you heat something in a microwave, there will be parts that are really hot, in close proximity to parts that are really not hot or even still frozen if what you were heating started frozen. There probably is not enough liquid substance in a block of wood or a racket to get any substantial heating from 60 seconds in a microwave. But I could be wrong and this could be tested with a regular block of wood that has no metal. If the theory is correct the block of wood, or even a wooden bowl, should not heat up. Then, if you took some water and put it in the wooden bowl, the water will heat up, and it, being heated, will heat the bowl.
Try with just some regular wood and see if it gets heated. 60 seconds should be a good test.
I think this idea may have come from people reading about blades like the Andro Temper Tech or Donic Burn. But I am guessing that what ever those companies are doing to the wood, and I think those blades are nice, I know the Temper Tech ones are, what ever the process is, the marketing descriptions are not giving you a real, full picture of the process.
And 10-30 seconds in a microwave would not cause the wood to be lighter, lose moisture and harden the surface. That sounds like fantasy.

If it was able to do that, 10-30 seconds in a microwave would give you a blade with a very inconsistent topsheet since only parts of the blade would be hit by the microwave at a time. Like that piece of food that is steaming hot in one place and sort of cold in another.