Some Sonnets about Time
There are many, many sonnets that mention time (you can search for the word "time" at Sonnet Central). One of my favorites, "Our Bias," by W. H. Auden, is still under copyright, so we can't include it here, but I've listed a few other selections below.
Sonnet 12 by William Shakespeare
When I do count the clock that tells the time,
And see the brave day sunk in hideous night;
When I behold the violet past prime,
And sable curls, all silver'd o'er with white;
When lofty trees I see barren of leaves,
Which erst from heat did canopy the herd,
And summer's green all girded up in sheaves,
Borne on the bier with white and bristly beard;
Then of thy beauty do I question make,
That thou among the wastes of time must go,
Since sweets and beauties do themselves forsake,
And die as fast as they see others grow;
And nothing 'gainst Time's scythe can make defence
Save breed, to brave him when he takes thee hence.
Clock java applet above by William Giel/Moondog Software.