Sliding glass windows should be given the same security treatment as arcadia doors. Use the same supplementary locks or screws in the frame. Screws installed in the track above the sliding window frame will prevent the window from being lifted out of the track.
Drill a pilot hole in the top track above each corner of the window frame and install a screw into each hole. Adjust the screws so that the head of the screw just barely clears the frame when it is moved back and forth.
Casement - Crank Windows
These windows are easily secured. The latch should close properly with the window tight. With the latch in a closed position, drill a small hole through the latch frame and handle. Insert a metal pin through the hole to lock the window.
For additional security, a small padlock can be used in place of the pin. Key operated replacement latches are also available from a locksmith or hardware store. Keep the key handy in case of emergency.
Double Hung Windows
An easy, inexpensive way to secure your windows is to use the "pin" trick. Drill an angled hole through the top frame of the lower window partially into the frame of the upper window. Then insert the pin (a nail or an eyebolt that is slightly smaller in diameter than the hole). The window can't be opened until you remove the pin. Make a second set of holes with windows partially open so you can have ventilation without inviting intruders.
You also may purchase special key locks for windows at a hardware store.