Broken bottles are used for stabbing and slashing attacks, so you use the same kinds of techniques you learn against knives to defend yourself against broken bottles – although broken bottles are more limited in their possible targets since it’s harder for them to penetrate clothing.
Ju-Jitsu teaches defences against two kinds of bottle: an ordinary bottle and a broken bottle. Ordinary bottles can be used as clubs to strike you downwards on the head or backhanded to the face. Armlocks can be used against the first kind of attack, while both armlocks and wristlocks can be used as defences against backhand attacks. Throws are not normally recommended because a flying bottle or glass might hit and hurt you.