Most lines of the poem end with long vowels. How do they contribute to the meaning of the poem?
Poets in the Renaissance period often expressed their faith in the permanence of poetry by boasting about the immortality of their verse. *Hint
Very difficult to respond without being told which sonnet you are looking at! There are a number by Shakespeare which deal with the same theme.
As a general point, long vowels would serve to elongate the lines and delay the movement onto the next line, imitating the way in which the poem would delay or prevent the memory of the subject being lost.