Masonite is a worldwide distributor of doors for both commercial and residential markets. While the company makes many types of doors, it is best known for its selection of wood doors. They are available in a variety of finishes, and many include integral windows, often called "lites." If the glass panel on your door is broken or you simply want a new look, it's fairly easy to remove and replace the glass yourself.
Examine both sides of the door carefully. On one side, the glass door panel will be held in by caulk and wood beads (trim). You will be able to see nail holes in the trim around the glass, and there will be clear joints between the trim and the rest of the door. On the other side, the trim is actually part of the door. You will only be working on the side that is removable, which is where you see the nails and/or caulk.
Cut away the caulk surrounding the glass and wood bead using your utility knife. Work carefully so you do not damage the trim.
Pry the wood beads away from all four sides of the glass using a hammer and chisel. Remove the nails from these wood trim pieces and set them aside for reuse.
Remove the existing glass panel from the door. It is best to wear gloves, and always use caution when handling glass. Wrap the glass in newspaper and tape it tightly shut before disposing of it.
Purchase a new piece of glass that is the same thickness as your old glass. You will need glass that is 1/8-inch smaller than the opening, both vertically and horizontally. For added safety, choose laminate or tempered glass. These materials will break into many small pieces if damaged, unlike regular glass, which can break into dangerous shards. You can purchase this material at a home improvement or hardware store. Masonite also offers specialty designer glass panels on its website.
Set the new panel into the opening. Use a clear silicone to caulk the glass into place.
Replace the wood trim and nail it into place using small finish nails. Remember that you are not trying to secure the trim to the glass. Instead, angle the nails so they penetrate the wood around the glass.