Nearly 1,000 entry-level employes of the New York State Department of Taxation and Finance were offered the chance last year to take the summer off, without pay. The TOTS (Take Off The Summer) Project was designed to improve morale, reduce costs and create more summer jobs for college students. It was so successful with both management and employes, that it was expanded this summer to include professional and technical workers as well.

United California Bank was troubled by a high turnover rate among part timers, many of whom worked nearly 30 hours a week without receiving fringe benefits. Management restructured its part-time employment into two categories: "hourly workers" who put in fewer than 20 hours a week and are not eligible for benefits, and "modified full-time employes" who work more than 20 hours a week and receive the same benefits as full timers. Vacation and sick leave are pro-rated according to hours worked. Since the change, the turnover rate has decreased and hiring and training costs have been reduced.

Those examples are among an increasing number of innovative employment plans presented at a conference on "Population Trends and Alternative Work Options," sponsored by the Congresswomen's Caucus. The focus was work alternatives -- phased retirement, job sharing, flexible leave, shortened and compressed work weeks -- devised to meet demands of a changing workforce.

"Some very strong demographic and labor market trends will influence job options in the future," predicted former secretary of labor Ray Marshall at last week's conference in the Rayburn Building. "Perhaps the most important . . . is the increased labor force participation by women.

"The absence of such family-enhancing matters as child-care facilities, flexible working times and programs to make it possible for women to enter, re-enter and stay in the work force, will have a strong impact on American families, and this in turn has a major impact on delinquency, the development of children and other social problems . . . Many of the public-policy issues of this decade will focus on the workplace."

The increased educational level of American workers, he told the some 150 corporate, union and legislative representatives, has resulted in a "strong demand for 'good' jobs, and a growing tendency to avoid marginal, disagreeable, low-wage jobs. Also, more highly educated workers wish to have greater participation in job decisions.

"The desire for participation, plus the greater work efficiency achieved through worker participation in Japan, Germany and Scandinavia will undoubtedly intensify pressures for some forms of worker participation in the United States.

"While all the returns are not in, there is considerable and consistent evidence that good industrial-relations systems containing worker participation can improve morale, motivation, productivity and efficiency."

Other trends that will create a demand for alternative work options, said Sara Rix of the Women's Research and Education Institute, include future labor shortages -- particularly among young workers -- an increase in single-parent and dual-career families, earlier retirement and greater competition for jobs among "baby-boomers."

The best-known alternative work schedules are flexitime and compressed work weeks (usually a four-day-week), said Gail Rosenberg, president of the National Council for Alternative Work Patterns. A newer approach being tried by corporations, she says, is "work sharing."

These plans all involve reduced work hours for employes, said Rosenberg, who has co-authored a book of 36 "work-sharing" case studies to be published next month by the Upjohn Institute. The three basic categories of "work sharing" are:

* Temporary reduction in work hours.

* Permanent reduction in work hours.

* Flexible work-life options.

"Temporary reductions in work hours," said Rosenberg, "are short-term strategies adopted for a limited time during an economic downturn, with pay reduction." Two types are a shortened workweek for all employes, and "rotation layoffs," in which all affected employes rotate weeks of work with weeks of nonwork (sometimes collecting unemployment insurance benefits).

Permanent reduction in work-hour plans include shorter workweeks (with or without reductions in pay and benefits), extended holidays and vacations and job-sharing.

"The third category, flexible worklife options," said Rosenberg, "are probably the least familiar to employers, but are now generating more interest. They provide periodic breaks in work lives of full-time employes." Among the most popular:

* Voluntary time-income tradeoffs -- contractual arrangements that allow full timers to voluntarily reduce their wages or salaries in exchange for additional time off.

* Leaves--sabbaticals or paid blocks of time away from work to pursue leisure, educational or personal interests or social-service projects.

* Phased retirement--gradual reduction of weekly work hours or chunks of time off for older employes before full retirement.

Companies should take note, said Richard Kinney of the J.C. Penney Corp., "that the No. 1 recommendation of the White House Conference on Families was that business, labor and government implement personnel policies that will enable people to hold jobs and still have a strong family life."

Among the advantages for companies that institute alternative work options, he said, are improved productivity, morale and job satisfaction, reduced absenteeism and tardiness and the ability to attract and retain good employes.

Disadvantages include possible disruptive effects, "supervisor's perceived loss of control," increased paperwork, the potential for abuse and managerial resistance to change. "My opinion," said Kinney, "is that the advantages outweigh the disadvantages."

About 15 percent of all federal, non-Postal Service personnel have participated in an "Alternative Work Schedule Experimental Program," which began in March 1979. About half are involved in flexitime programs and half compressed work schedules.

The report on the experiment, expected to be submitted to Congress this week, "indicates that over 90 percent of employes and 85 percent of supervisors consider it a success," says the Office of Personnel Management's Raymond Kirk. "Over 80 percent of the agencies that experimented plan to continue."