The daylight spell is cast on an object, but what happens to the spell if the object is destroyed? Does the spell dissipate because its target no longer exists, or do the pieces of the destroyed object continue to glow for the duration of the spell?
Daylight depends on having one discrete object to 'hold' onto. This interacts a little oddly with items being broken or destroyed, so lets' take a look.
In the vast generality of cases, items that are broken are still identifiable as the original object and can still 'hold' a spell though they may be missing pieces. The key part of this is that the item could still be put back together through mundane or magical means. Therefore, if you cast Daylight on my shield and a blind orc somehow sunders it (which makes the item broken), the spell will hang around on the item as long as everything is still together, IE if my shield is still a shield.
Of course, this doesn't hold up as well if that same shield has Disintegrate cast on it. A destroyed object isn't identifiable as the original object and any spells on the object dissipate. The important thing to note here is that you're looking at something that has been utterly taken out of its form. Another good example is if my shield were to be tossed into lava. The spell will last as long as the shield is still a discrete object. But the instant that thing loses its form and melts down, the spell ends.