This is a difficult question to answer as it also depends on the severity of the impact suffered by the bottle:

If the glass is just cracked it may take time (minutes to hours) for the chloroform to seep through the cracks and dissolve the polyurethane.
Whereas if the impact was so severe that glass fragments were detached from the polyurethane coating, the chloroform would be immediately in direct contact with the polyurethane.

Polyurethane is highly soluble in chloroform; so once chloroform is in direct contact; it will dissolve the bottle coating in approximately 10 – 30 seconds.