Glare

Glare is a negative sensation or perception that results from excessive
brightness in the field of view.
glare is a perception, not a physical object or event
glare is relative -- because brightness is relative
glare is relative -- because excessive is relative
glare is always negative (no good glare, bad glare)
glare is fairly commonly experienced
the potential for glare can be reduced through design

Sparkle

Sparkle is a positive sensation or perception that results from excessive
brightness in the field of view.

References: From class notes.
More information about Glare:
Degrees of Glare
Sources of Glare