The first is use a plastic saw blade. ( I know: bad sentence, bad sentence.)(meaning a saw blade made for cutting plastic moulding, and not a saw blade made of plastic, but that might be interesting too . . .).
Second: Have the blade pass thru the material the correct speed. The melting comes from the material rubbing on the side of the blade . A faster pass gives less rubbing. Pretty much you cut the stuff as fast as you can, if not faster. Count fingers when done.
Here is an anolgy: If you have a leaky tire you can either just keep filling it when it gets low or actually remedy the problem in a more permanent way (fix it, or buy a new one, and take those pesky nails out of the driveway).
Part of the niche plastic mldg fills is the low end. If you need to spray after each cut, the mldg is still cheap, but you take longer to cut it, and expend spray, and may addl cleanup needed (actual cost to produce goes up). If you cut it as fast possible you will be cutting it faster than wood or metal (cost to product goes down).
But if you are just cutting a few. And only once in a while; If it ain't fix, don't broke it.
But I do hope that if you are doing 8 sprays per frame you are wearing a respirator or at least a dust mask. The silicone does wonders for the lungs. Come to think of it, so does the plastic moulding. And the glue used to glue it.
BTW (by the way): What glue are you using to glue it? Regular wood glue or the super glue, melty stuff?