to evolve
'To improve' means 'sudharana'.
She gradually made her way up the beach. -V.Cain Gradually means to progress, but to progress slowly. -V.Cain
"Crescendo", means to gradually increase in size, intensity or force.
One word that fits is corrosion.
Progress.
Slow or improve
progress
Its called weening
the word in music that means gradually getting louder and louder is a cresendo!
Fade or melt would fit.
Improve