Relay can operate with both , AC and DC. The same time, switching on/off usually slow for regular relay. There are also solid state relay on a market, which is fast. Or you can build your own driver based on this drawings:
http://ruggedcircuits.com/html/circuit__7.htmlCCFL package includes rectifier (HV converter, probably, right name for it), so it's not clear how fast this devise on start-up. I mean, you could build a circuitry, but if there is a big delay in switching rectifier , than you'd also have to build another rectifier/converter...