isolated high voltage H-bridge
As you've realized, driving a gate with 100 volts is not a great idea. Neither is trying to switch 100 volts with an optocoupler with a maximum collector-emitter voltage of 70 volts (see page 3 of the data sheet). Input-output isolation voltage is NOT output operating voltage.

Dwayne Reid has also pointed out the folly of your schematic due to what's called "shoot-thru" current, which occurs when both the upper and lower transistors on one side are both turned on.

A basic approach might look like







simulate this circuit &ndash; Schematic created using CircuitLab

You'll need some logic to insert delays into the optocouplers so that you don't get shoot-thru, but since you've got separate optocouplers you should be able to do that without too much fuss.

Do note that if there is no optocoupler drive you'll burn out the FETs (or at least drive the 100 volt supply into current limit), so you'll need to be careful of your board interlocks.