Joy Joy Joy Joy

"When the last movement had gone round for the second time with all the banging and creeching about Joy Joy Joy Joy, then these two young ptitsas were not acting the big lady sophisto no more. They were like waking up what was being done to their malenky persons and saying that they wanted to go home and like I was a wild beast. They looked like they had been in some big bitva, as indeed they had, and were all bruised and pouty. Well, if they would not go to school they must still have their education. And education they had had. They were creching and going ow ow ow as they put their platties on, and they were like punchipunching me with their teeny fists as I lay there dirty an nagoy and fair shagged and fagged on the bed. This young Sonietta was creeching. 'Beast and hateful animal. Filthy horror.' So I let them get their things together and should be got on me and all that cal. Then they were going down the stairs and I dropped off to sleep. still with the old Joy Joy Joy Joy crashing and howling away" (Burgess).

The main character, Alex, is what we, in our society, would most likely call a barbarian or something of the sort, but he doesn't realize that he's doing anything wrong. For Alex, dinner and raping and mugging someone fall under the same category, they are amatory acts of like. Alex is completely evil, or so he seems at this point in the book. Which I find kind of intriguing, because I know that in the last chapter he will become 'good'.
I don't understand how someone, who has lived with such a bloodcurdling society, can just change. I can understand that over time a person can look at everything their life has culminated into and realize that they don't like what they see, and I know Alex does that, but he does it so suddenly. I want to know how, when and why this change arouses in his life. Because I just don't understand how it can happen so abruptly.
But, there are a few clues that can show that this climax is going to happen. He like Beethoven. Which does not exactly fit into his rebel-esk like style.