If you are using polycarbonate (Lexan) you will not be able to heat it to make a compound curve without distorting it's clarity. Polycarbonate tends to bubble when it gets hot enough to bend.
If you are using acrylic (Plexyglass) you will need to heat the whole sheet and form it at a temperature of around 350 degrees F. It is usually formed over a buck or by holding/clamping it at the edges and letting it sag with the heat.... good luck.
Ralph