Rhyme in Elizabethan sonnets

If you believe David Crystal's reconstructions of Elizabethan pronunciation, you can check out the Romeo and Juliet recording on this page. There both "love" and "remove" are pronounced with a vowel very much like that in the modern "love", but shorter. I know his work is well-respected enough that the Globe has used it in a few productions, but I believe it's not universally agreed with, so treat this with a moderate amount of skepticism.

Rhyming words based on spelling when they are not pronounced the same is called variously "eye rhyme", "sight rhyme", or "visual rhyme".

This may occur due to historical changes in word pronunciation, where words in the rhyme were once pronounced the same, but no longer are. However, it is also a valid poetic device; the presence of eye rhyme does not necessarily mean that the pronunciation of words has changed.

This resource indicates that the love/move/prove rhyme results from a change in pronunciation, but does not say which words changed.

According to "Early Modern English" by Charles Laurence Barber, the vowel o in love had already reached its current pronunciation /lʌv/ (same sound as in cup, luck), but an alternative pronunciation /lu:v/ was in common use by poets (same sound as in blue).

Certainly the following piece¹ is not a complete answer to your question, but, for the reason that there is an interesting fragment on the drift of "ove", I decided to post that as a little contribution.

In England the Great Vowel Shift, as it is generally and somewhat misleadingly called, happened later, roughly around the time of Chaucer. Textbook discussions of the shift can sometimes leave us with the impression that people pronounced their vowels in one way up to a certain date and then suddenly, as if on a whim, began pronouncing them in an altogether different way. But of course it was never as simple as that. Many of the pronunciation changes reflected changes that had begun centuries before in the time of King Alfred and some of them are not complete to this day. (Shove and move may one day be pronounced in the same way; it would make sense.) So, although it is true to say that these constituted some of the most sudden and dramatic changes English had ever undergone, we should not lose sight of the fact that we are talking about a period that spanned, even at its most rapid, a couple of generations. When Chaucer died in 1400, people still pronounced the e on the end of words. One hundred years later not only had it become silent, but scholars were evidently unaware that it ever had been pronounced. In short, changes that seem to history to have been almost breathtakingly sudden will often have gone unnoticed by those who lived through them.

No one knows why this vowel shift happened. As Charlton Laird has succinctly put it: "For some reason, Englishmen started shoving tense vowels forward in their mouths. Then they stopped. And they have remained stopped. Nobody knows why they started or why they stopped." For whatever reasons, in a relatively short period the long vowel sounds of English (or tense vowels as Laird called them) changed their values in a fundamental and seemingly systematic way, each of them moving forward and upward in the mouth. There was evidently a chain reaction in which each shifting vowel pushed the next one forward: The "o" sound of spot became the "a" sound of spat, while spat became speet, speet became spate, and so on. The "aw" sound of law became the "oh" sound of close, which in turn became the "oo" sound of food. Chaucer's lyf, pronounced "leef," became Shakespeare's life, pronounced "lafe," became our life. Not all vowels were affected. The short e of bed and the short i of hill, for instance, were unmoved, so that we pronounce those words today just as the Venerable Bede said them 1,200 years ago.

[...]

Before the shift house was pronounced "hoose" (it still is in Scotland), mode was pronounced "mood," and home rhymed with "gloom," which is why Domesday Book is pronounced and sometimes called Doomsday. (The word has nothing to do with the modern word doom, incidentally. It is related to the domes- in domestic.) But as with most things, shifting vowel sounds were somewhat hit or miss, often because regional variations disrupted the pattern. This is most notably demonstrated with the "oo" sound. In Chaucer's day in London, all double o words were pronounced to rhyme with the modern word food. But once the pattern was broken, all kinds of other variations took hold, giving us such anomalies as blood, stood, rood, and so on. Most of these words were pronounced in different ways by different people from different places until they gradually settled into their modern forms, although some have never truly settled, such as roof and poof, which some people rhyme with goof and others pronounce with the sound in foot. A similar drift with "ove" accounts for the different sounds of shove, move, and hove.

¹ Mother Tongue, Bill Bryson, Penguin Book.