"I will be glad when I see you" is correct but more common is "I will be glad to see you". Note you must capitalise the first person singular pronoun in English.

Please use capital letters - there are not optional. "I'll be glad when I see you." "I'll be glad to see you." "I'm glad when I see you." "I'm glad to see you." These all have different meanings - which one were you thinking of?