2006 Toyota Avalon sideview mirror

Visit a glass company. Some of them have access to just the mirror glass that is already cut to fit your application. They can sell you a tube of adhesive, or you can use silicone gasket sealer. The Chrysler dealer's parts department has that in black and gray. The black stuff stays more rubbery and is easier to remove. The gray stuff gets harder and is stronger for this type of application. Other manufacturers have similar products with their own names on them. I happen to be familiar with Chrysler's products.

You might be able to order just the glass through the dealer too.