Glow of pipe, crack-smoker occasionally managed to get inside (9)

'glow' is the definition.
(I know that fluoresce is a more specific form of the action glow)

'pipe crack-smoker occasionally managed to get inside' is the wordplay.
'pipe' becomes 'flue' (flue is a kind of pipe).
'occasionally' indicates alternate letters (letters taken at regular intervals or occasions).
'managed' indicates an anagram.
'to get inside' is an insertion indicator.
'crack'+'smoker'='cracksmoker'
The alternating letters of 'cracksmoker' are 'rcsoe'.
'rcsoe' with letters rearranged gives 'oresc'.
'flue' placed around 'oresc' is 'FLUORESCE'.

'of' is the link.