According to Steven Pinkerin The Language of Instinct: How the Mind Creates Language: "The reason we say razzle-dazzle rather than dazzle-razzle is because the word beginning with the less obstruent consonant (one you pronounce by forcing air through an obstruction) always comes before the word beginning with the more obstruent consonant."

A more general way of saying that is that the more euphonic would pevail