Nancy, it may not be what you want to hear but Mike from Homeworks answer to your earlier post sounds right on to me. Plexiglas or similar can work great for a backsplash where you have adequate clearance from the stove and are basically concerned about occasional grease spatters. If it was me, I would be sure there was a cementacious backer board and install ceramic tile. While drywall is fire resistant, I would be a lot more comfortable with a product that was even more so. If your stove is close enough to your walls for you to be concerned about scorching them, you should be concerned about a possible fire hazard.