The Austrian, who led the Eagles to their first major trophy by winning last season's FA Cup, is set to be out of contract in June.
Speculation has rumbled over Glasner's future and he addressed the noise by revealing that he told club chairman Steve Parish he will not be signing new terms at Selhurst Park.
"A decision has already been taken, months ago," Glasner told reporters at a press conference on Friday. "I had a meeting with Steve (Parish) in October, the international break.
"We had a very long talk, and I told him I will not sign a new contract.
"We agreed at the time it was best to keep it between us. It's the best that we could do that and keep it confidential for three months.
"But now it's important to have clarity, and we had a very busy schedule, so that's why we didn't want to talk about it. Steve and I want the best for Crystal Palace."
Glasner added his decision was driven purely by a desire for a fresh chapter in his career and was not influenced by the club's operation in the transfer market.
"I told Steve I'm just looking for a new challenge," Glasner said. "I told him in October, it's nothing to do with the transfer window.
"I hate if something is written or said that is not true, and it was very tough for me not to respond. We have a great relationship, and we're always talking about what is best for Crystal Palace."
Glasner has recently been linked with the Manchester United job, which has been taken by Michael Carrick on an interim basis until the end of term.
However, the 51-year-old insisted he has not been in contact with any other club about a new role and his main focus is on Palace's European endeavours in the Conference League.
"I haven't spoken to any other club, I told the players that and promised them today I will give my best to give the best season in Crystal Palace history.
"We are now four points better off than we were at this stage of the season, and we will do everything to bring another trophy back to Selhurst Park.
"We had the Conference League draw today, we will play Zrinjski Mostar from Bosnia in the play-off draw, and I had a look at the draw tree, it'll be quite interesting who we could play in our section.
"I will do everything to help bring a trophy back to Selhurst Park."
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