Brief period of enchantment (5)
I believe the answer is:
spell
This clue is a double definition.
'brief period' is the first definition.
(I've seen this in another clue)
'enchantment' is the second definition.
(I know that enchantment can be written as spell)
'of' is the link.
(Other definitions for spell that I've seen before include "Fascination" , "Write letters correctly" , "Short period of time; incantation" , "... mean" , "Name in order the letters of the alphabet involved" .)