Re: Why is there no phase change for internal reflecti

Utilize this experiment.  Tie a rope onto a solid object.
Make transverse waves.  Notice upon reflection they return
upside down (180 degrees out of phase).  The boundary represents
the denser medium the wave reflected from.  When wave undergo
reflection from less dense to a denser medium, there is a phase change.

Now tie the rope to a hollow cylinder, and place the cylinder
around a stationary rod so it will slide up and down.  Repeat the
experiment.  This represents a less dense boundary.  When waves reflect
off this they return without a 180 degree change.

Since total internal reflection represents reflection off a boundary
from denser to less dense material, no phase change exists.