A partitive article is just one instance when you would use a definite article, precceded by de. It contracts like it normally would in other instances:
Donnez-moi les lunettes, svp. -- Give me the glasses, please. (simple definite article)J'ai besoin des lunettes. -- I need glasses. (partitive article: des = de + les)Vous pensez des lunettes? -- Are you thinking of glasses? (normal contraction)
