On rollover blur movieclip

1

i have some buttons and movieclipss. when roll over to the buttons i want to make some mc’s alpha 30.

here is my code for buttons


on (rollOver) {
    setProperty("_root.oyun", _alpha, "30");
    setProperty("_root.galeri", _alpha, "30");
    setProperty("_root.gunluk", _alpha, "30");
    setProperty("_root.galeri", _alpha, "30");
    setProperty("_root.chat", _alpha, "30");
    setProperty("_root.forum", _alpha, "30");
    setProperty("_root.etkinlik", _alpha, "30");
    setProperty("_root.profil", _alpha, "30");
}
on (rollOut) {
    setProperty("_root.oyun", _alpha, "100");
    setProperty("_root.galeri", _alpha, "100");
    setProperty("_root.gunluk", _alpha, "100");
    setProperty("_root.galeri", _alpha, "100");
    setProperty("_root.chat", _alpha, "100");
    setProperty("_root.forum", _alpha, "100");
    setProperty("_root.etkinlik", _alpha, "100");
    setProperty("_root.profil", _alpha, "100");
}

ok this is working but this set the alpha property very fast (instant) how can i make them to change their alpha by level, level (like motion tween)