Hello!
you can do a script like the following
On the event you want to start to dissolve the material, change the parameter of the Ammount of the dissolve, and have another variable that contains the float of the final dissolve, and if the current dissovle ammount is less or equal to the final dissolve ammount, you can fire the event OnDissolveComplete
in order for the dissolve ammount to animate, you should use a timeline and a lerp node
Hope this helps!