This article has a nice analysis of the Orcs aversion to sunlight.
The sunlight seemed to have more of a psychological effect on the orcs, much like the gloom of Mordor depressed the morale of all men who entered there. Many times throughout the Silmarillion Orcs fight in the sunlight, fueled on by either hate of their enemies or fear of their dark masters.
So in a sense they hate the light, and would rather not be in it, but when forced to, they can travel and fight normally. The main passage of interest from LOTR, when Aragorn and company are pursuing the Uruks:
The orc-band began to descend a narrow ravine leading down into the
misty plain below. Merry and Pippin, separated by a dozen Orcs or
more, climbed down with them. At the bottom they stepped on to grass,
and the hearts of the hobbits rose. ‘Now straight on!’ shouted Uglúk.
‘West and a little north. Follow Lugdush.’
‘But what are we going to do at sunrise?’ said some of the
‘Go on running,’ said Uglúk. ‘What do you think? Sit on the grass and
wait for the Whiteskins to join the picnic?’
‘But we can’t run in the sunlight.’
‘You’ll run with me behind you,’ said Uglúk. ‘Run! Or you’ll never see
your beloved holes again. By the White Hand! What’s the use of sending
out mountain-maggots on a trip, only half trained. Run, curse you! Run
while night lasts!’
Then the whole company began to run with the long loping strides of
Orcs. They kept no order, thrusting, jostling, and cursing; yet their
speed was very great. Each hobbit had a guard of three. Pippin was far
back in the line. He wondered how long he would be able to go on at
this pace: he had had no food since the morning. One of his guards had
a whip. But at present the orc-liquor was still hot in him. His wits,
too, were wide-awake.