SANTA BARBARA, CALIF., AUG. 18 -- White House officials expressed pleasure today that American journalist Charles Glass had obtained his freedom in Lebanon but said there were no signs that any of the eight other American hostages remaining in captivity there were about to be released.

The White House reacted cautiously to the reports of Glass' release. White House spokesman Marlin Fitzwater said that President Reagan was "glad" that Glass was freed and "grateful for whatever assistance the Syrians had provided" in the matter.

Another senior official, who declined to be identified, said that no conclusion had been drawn on whether Glass had actually escaped or whether he had been allowed to leave by his captors. In any case, this official said, the freeing of Glass was regarded by the administration as "a singular event" that did not necessarily mean that other hostages would be freed.

The administration view is that the Syrians have exerted heavy pressure on the extremist Shia Muslim group that kidnaped Glass, a former ABC News correspondent, to release him. He was seized June 17 by 14 gunmen who also abducted Ali Osseiran, son of Lebanon's defense minister. Osseiran was subsequently released.

Reagan, vacationing at his mountaintop ranch northwest of here, was informed of Glass' release this morning in a telephone conversation with his national security adviser, Frank C. Carlucci, who is in Santa Barbara.

But officials here said the White House had a sketchy report of what happened because Glass was interviewed only briefly before he was driven to Damascus by Syrian troops for a flight to London.

Leslye Arsht, a deputy White House press spokesman, said Glass was "in good health" and was expected to provide details of his capture and escape when he is interviewed by an interagency team of administration officials in London. She said that the president also hoped that other Americans held hostage in Lebanon would be able to obtain their freedom.