For the first time in its 48-year history, the Radcliffe Library will stay open until 11 p.m. during reading period and exams this spring, Ruth C. Porritt, College Librarian, announced yesterday.

The hours have been extended in response to repeated student demands, brought out at this year's Cedar Hill Student Government conference. Unless a sufficient number of students, "approximately 35," make use of the library from 10 to 11 p.m., Miss Porritt said, the experiment will not be repeated.

The difficulty of staffing the library at night has always been the principle objection to extending its hours, she said. At present, the regular staff will be sufficient to service the library during the extra hour in the evening. The library will also be open from 3 to 5 p.m. on Sunday afternoons but for study purposes only. No books may be borrowed or returned then, she said.

Miss Porritt also revealed that the library has just received nearly 500 books on international relations from the estate of Sarah Wambaugh, Radcliffe '02. Miss Wambaugh was a leading authority on international law, specializing in plebes-cites.