I was watching this game last night too! The tv guys were talking about his new pads at the begininng of the game and they too didnt know why he changed during the intermission either...well here is why...source is TSN.

"GIslanders goaltender Rick DiPietro could be facing a suspension for using illegal equipment after playing the first period of Thursday's game against the Panthers with pads that had not been inspected by the league.
Goalie equipment must be inspected and approved by the NHL before it can be used in a game. Using illegal or uninspected equipment results in an automatic two-game suspension for the player and fines of $25,000 for the team and $1,000 for the equipment manager. DiPietro changed into his old pads in the first intermission. - New York Newsday "