> I'm aware of two kinds of vowel nasalization. Nasalization
> throughout the vowel (as in French), or nasalization of the
> final part of the vowel (as in Portuguese or Polish). There
> is no standard way in IPA to distinguish between the two.
Unless you transcribe the latter overtly as diphthongs, which they
normally are in both Polish and Portuguese. The offglide is a strongly
nasalised high semivowel, [j~] or [w~]. For example, the most usual
pronunciation of my name (<Ga,siorowski>) is [gOj~s\O"rOsci]. The
duration of the Polish nasal vowels is approximatly twice that of the
corresponding oral ones (there is no phonemic distinction of quantity in
the language), which is a strong argument in favour of treating the
nasal ones as sequences rather than single segments.