It is possible to change the look of a dark hallway by replacing panels in the external door with glass. However you must be security minded and think of the implication of someone smashing the glass. Make sure you have adequate security to counteract any criminal act. A mortise lock is essential as the locking device can be key locked and would require a key to unlock it.
Always hang the door before carrying out any glazing. Once the door fits in the doorway, it can be removed for any extra work on its surface. Remove the beading on the top panels and take out the wooden panels, using a hammer and chisel. Take care, as the beading may be able to be used again when securing the glass panels. You should use toughened glass in the doors for safety. Safety glass is heavy and sharp, so always wear gloves when moving it. The glass can be obscure or clear. The door should be rubbed down and painted before the glass panels are positioned in the door.
Use putty and beading to fix the glass securely in position on the door.