Two Virginia men have set up a special trust fund totalling $550,000 for the College of William and Mary but specified that it may not be withdrawn until the year 2076 when, according to one estimate, interest will have swelled the sum to $150 million.

That estimate came from officials of the college, who also noted that $150 million is more than 10 times their present endowment.

The money to be available to the Williamsburg, Va., college in the nation's tricentennial year is called the "Tricentennial Fund." Hinton T. Smith, 80, a William and Mary graduate in 1918, has provided $550,000 in his will for it, and Thomas P. Duncan, a Newport News businessman whose wife attended the college already has given the fund $50,000, a college spokesman said.

Smith's will provides that the money will go to the Tricentennial Fund and another $500,000 will go to, only after his wife's death, if he dies before she does. But there would be no delay in a seperate gift of $25,000 for the college's unrestricted use, also provided for in Smith's will.

Smith, who lives in Boykin, Va. said he is proud of his college, the second oldest in the nation. He said he has given it $1,000 annually in recent years.

The retired officer of the Virginia National Bank said in a telephone interview he frequently attends football games at William and Mary, although when he first went there in 1914 he didn't know much about the sport.

"I came from a little country school and we didn't have football games in those days," said Smith, who recalled there were about 300 students at the college in 1914. It now has about 6,000. He said he sometimes travels with the football team to games at other schools.

Under provisions of the will, a special trust fund of $1 million will be set up for his wife, Thelma, with the interest from the fund supporting her during her lifetime after his death.

Uopn his wife's death, $500,000 will be placed in the Tricentennial Fund, where it will draw interest until 2076. The other $500,000 will be given to the athletic fund.

A college spokesman said the $500,000 for the Tricentennial Fund, invested at 7 per cent interest in the year 2000, would be worth $100 million by 2076.

The $50,000 already contributed by Duncan will be worth an estimated $50 million by 2076, the spokesman said. CAPTION: Picture 1, Hinton Smith of Boykin, Va., William & Mary class of 1918; Picture 2, and the campus of his alma mater at Williamsburg where $150 million will be added to the college endowment in the 21st century. AP